0001528287-21-000018 | 10-Q | XBRL Viewer

Print Document View Excel Document

Cover - shares	9 Months Ended
Cover - shares	Sep. 30, 2021	Nov. 09, 2021
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2021
Document Transition Report	false
Entity File Number	001-40337
Entity Registrant Name	NEUROPACE, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	22-3550230
Entity Address, Address Line One	455 N. Bernardo Avenue
Entity Address, City or Town	Mountain View
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	94043
City Area Code	650
Local Phone Number	237-2700
Title of 12(b) Security	Common Stock, $0.001 par value per share
Trading Symbol	NPCE
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		24,314,002
Amendment Flag	false
Entity Central Index Key	0001528287
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q3

Condensed Balance Sheets - USD ($)	Sep. 30, 2021	Dec. 31, 2020
Current assets
Cash and cash equivalents	$ 26,633,000	$ 26,390,000
Short-term investments	96,701,000	11,689,000
Accounts receivable	6,611,000	8,395,000
Inventory	7,162,000	6,909,000
Prepaid expenses and other current assets	3,383,000	1,179,000
Total current assets	140,490,000	54,562,000
Property and equipment, net	624,000	515,000
Restricted cash	122,000	366,000
Deferred offering costs	0	484,000
Other assets	21,000	23,000
Total assets	141,257,000	55,950,000
Current liabilities
Accounts payable	1,254,000	949,000
Accrued liabilities	7,420,000	6,603,000
Short-term debt	0	2,043,000
Total current liabilities	8,674,000	9,595,000
Deferred rent, noncurrent	1,041,000	1,301,000
Long-term debt	49,582,000	50,821,000
Redeemable convertible preferred stock warrant liability	0	369,000
Other liabilities	248,000	274,000
Total liabilities	59,545,000	62,360,000
Commitments and contingencies (Note 5)
Redeemable convertible preferred stock, $0.001 par value - no shares authorized as of September 30, 2021 and 60,757,386 shares authorized as of December 31, 2020, respectively; no shares issued and outstanding as of September 30, 2021 and 16,614,178 shares issued and outstanding as of December 31, 2020, respectively (Liquidation value $0 and $227,755 as of September 30, 2021 and December 31, 2020, respectively)	0	141,422,000
Stockholders’ equity (deficit)
Preferred stock, $0.001 par value, 10,000,000 shares authorized; no shares issued and outstanding as of September 30, 2021 and December 31, 2020	0	0
Common stock, $0.001 par value - 200,000,000 shares and 74,636,348 shares authorized as of September 30, 2021 and December 31, 2020, respectively; 24,307,898 and 314,096 shares issued and outstanding as of September 30, 2021 and December 31, 2020, respectively	24,000	0
Additional paid-in capital	494,733,000	239,826,000
Accumulated other comprehensive income	33,000	33,000
Accumulated deficit	(413,078,000)	(387,691,000)
Total stockholders’ equity (deficit)	81,712,000	(147,832,000)
Total liabilities, redeemable convertible preferred stock and stockholders’ equity (deficit)	$ 141,257,000	$ 55,950,000

Condensed Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Statement of Financial Position [Abstract]
Redeemable convertible preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Redeemable convertible preferred stock, shares authorized (in shares)	0	60,757,386
Redeemable convertible preferred stock, shares issued (in shares)	0	16,614,178
Redeemable convertible preferred stock, shares outstanding (in shares)	0	16,614,178
Redeemable convertible preferred stock, liquidation preference	$ 0	$ 227,755
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Shares authorized (in shares)	10,000,000	10,000,000
Preferred stock issued (in shares)	0	0
Preferred stock outstanding (in shares)	0	0
Common stock par value (in dollars per share)	$ 0.001	$ 0.001
Common stock authorized (in shares)	200,000,000	74,636,348
Common stock issued (in shares)	24,307,898	314,096
Common stock outstanding (in shares)	24,307,898	314,096

Condensed Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Income Statement [Abstract]
Revenue	$ 10,339	$ 12,771	$ 34,186	$ 30,386
Cost of goods sold	2,832	3,196	8,827	8,333
Gross profit	7,507	9,575	25,359	22,053
Operating expenses
Research and development	4,329	3,691	12,866	11,776
Selling, general and administrative	9,421	7,050	27,215	20,347
Total operating expenses	13,750	10,741	40,081	32,123
Loss from operations	(6,243)	(1,166)	(14,722)	(10,070)
Interest expense (includes $0 and $203 to related parties in the three months ended September 30, 2021 and 2020, respectively, and $0 and $1,258 to related parties in the nine months ended September 30, 2021 and 2020, respectively)	(1,826)	(2,792)	(5,548)	(9,603)
Other income (expense), net	(14)	(168)	(5,117)	13
Net loss	(8,083)	(4,126)	(25,387)	(19,660)
Unrealized gain on available-for-sale debt securities	22	4	0	0
Comprehensive loss	$ (8,061)	$ (4,122)	$ (25,387)	$ (19,660)
Net loss per share attributable to common stockholders, basic (in dollars per share)	$ (0.34)	$ (19.26)	$ (1.81)	$ (96.02)
Net loss per share attributable to common stockholders, diluted (in dollars per share)	$ (0.34)	$ (19.26)	$ (1.81)	$ (96.02)
Weighted-average common stock outstanding used to compute diluted net loss per share (in shares)	24,101,399	202,408	14,061,958	202,382
Weighted-average common stock outstanding used to compute basic net loss per share (in shares)	24,101,399	202,408	14,061,958	202,382

Condensed Statements of Operations and Comprehensive Loss (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Income Statement [Abstract]
Interest expense, related party	$ 0	$ 203	$ 0	$ 1,258

Condensed Statements of Redeemable Convertible Preferred Stock and Stockholders’ Equity (Deficit) - USD ($) $ in Thousands	Total	Redeemable Convertible Preferred Stock	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income	Accumulated Deficit
Beginning balance (in shares) at Dec. 31, 2019		635,048
Beginning balance at Dec. 31, 2019		$ 73,568
Ending balance (in shares) at Mar. 31, 2020		635,048
Ending balance at Mar. 31, 2020		$ 73,568
Beginning balance (in shares) at Dec. 31, 2019			202,121
Beginning balance at Dec. 31, 2019	$ (129,350)		$ 0	$ 234,290	$ 1	$ (363,641)
Increase (Decrease) in Stockholders' Equity
Net loss	(6,741)					(6,741)
Unrealized gain (loss) on available-for-sale debt securities	(41)				(41)
Issuance of common stock pursuant to stock option exercises (in shares)			131
Issuance of common stock pursuant to stock option exercises	6			6
Stock-based compensation	301			301
Ending balance (in shares) at Mar. 31, 2020			202,252
Ending balance at Mar. 31, 2020	(135,825)		$ 0	234,597	(40)	(370,382)
Beginning balance (in shares) at Dec. 31, 2019		635,048
Beginning balance at Dec. 31, 2019		$ 73,568
Ending balance (in shares) at Sep. 30, 2020		16,614,178
Ending balance at Sep. 30, 2020		$ 141,422
Beginning balance (in shares) at Dec. 31, 2019			202,121
Beginning balance at Dec. 31, 2019	(129,350)		$ 0	234,290	1	(363,641)
Increase (Decrease) in Stockholders' Equity
Net loss	(19,660)
Ending balance (in shares) at Sep. 30, 2020			202,252
Ending balance at Sep. 30, 2020	(143,736)		$ 0	239,336	1	(383,073)
Beginning balance (in shares) at Mar. 31, 2020		635,048
Beginning balance at Mar. 31, 2020		$ 73,568
Redeemable Convertible Preferred Stock
Series B’ redeemable convertible preferred stock issuance costs		$ (117)
Ending balance (in shares) at Jun. 30, 2020		635,048
Ending balance at Jun. 30, 2020		$ 73,451
Beginning balance (in shares) at Mar. 31, 2020			202,252
Beginning balance at Mar. 31, 2020	(135,825)		$ 0	234,597	(40)	(370,382)
Increase (Decrease) in Stockholders' Equity
Net loss	(8,793)					(8,793)
Unrealized gain (loss) on available-for-sale debt securities	37				37
Stock-based compensation	290			290
Ending balance (in shares) at Jun. 30, 2020			202,252
Ending balance at Jun. 30, 2020	(144,291)		$ 0	234,887	(3)	(379,175)
Redeemable Convertible Preferred Stock
Issuance of Series B’ redeemable convertible preferred stock (in shares)		7,599,720
Issuance of Series B’ redeemable convertible preferred stock, net of issuance costs of $1,187		$ 31,813
Conversion of convertible notes into Series B' redeemable convertible preferred stock (in shares)		8,379,410
Conversion of convertible notes into Series B' redeemable convertible preferred stock	4,148	$ 36,386		4,148
Reduction of Series A' redeemable convertible preferred stock liquidation value	228	(228)				228
Series B’ redeemable convertible preferred stock issuance costs		$ 1,187
Ending balance (in shares) at Sep. 30, 2020		16,614,178
Ending balance at Sep. 30, 2020		$ 141,422
Increase (Decrease) in Stockholders' Equity
Net loss	(4,126)					(4,126)
Unrealized gain (loss) on available-for-sale debt securities	4				4
Conversion of convertible notes into Series B' redeemable convertible preferred stock (in shares)		8,379,410
Conversion of convertible notes into Series B' redeemable convertible preferred stock	4,148	$ 36,386		4,148
Stock-based compensation	301			301
Ending balance (in shares) at Sep. 30, 2020			202,252
Ending balance at Sep. 30, 2020	$ (143,736)		$ 0	239,336	1	(383,073)
Beginning balance (in shares) at Dec. 31, 2020	16,614,178	16,614,178
Beginning balance at Dec. 31, 2020	$ 141,422	$ 141,422
Ending balance (in shares) at Mar. 31, 2021		16,614,178
Ending balance at Mar. 31, 2021		$ 141,422
Beginning balance (in shares) at Dec. 31, 2020	314,096		314,096
Beginning balance at Dec. 31, 2020	$ (147,832)		$ 0	239,826	33	(387,691)
Increase (Decrease) in Stockholders' Equity
Net loss	(8,810)					(8,810)
Issuance of common stock pursuant to stock option exercises (in shares)			156,538
Issuance of common stock pursuant to stock option exercises	4			4
Stock-based compensation	202			202
Ending balance (in shares) at Mar. 31, 2021			470,634
Ending balance at Mar. 31, 2021	$ (156,436)		$ 0	240,032	33	(396,501)
Beginning balance (in shares) at Dec. 31, 2020	16,614,178	16,614,178
Beginning balance at Dec. 31, 2020	$ 141,422	$ 141,422
Ending balance (in shares) at Sep. 30, 2021	0	0
Ending balance at Sep. 30, 2021	$ 0	$ 0
Beginning balance (in shares) at Dec. 31, 2020	314,096		314,096
Beginning balance at Dec. 31, 2020	$ (147,832)		$ 0	239,826	33	(387,691)
Increase (Decrease) in Stockholders' Equity
Net loss	$ (25,387)
Issuance of common stock pursuant to stock option exercises (in shares)	265,498
Ending balance (in shares) at Sep. 30, 2021	24,307,898		24,307,898
Ending balance at Sep. 30, 2021	$ 81,712		$ 24	494,733	33	(413,078)
Beginning balance (in shares) at Mar. 31, 2021		16,614,178
Beginning balance at Mar. 31, 2021		$ 141,422
Redeemable Convertible Preferred Stock
Net exercise of Series B’ redeemable convertible preferred stock warrants (in shares)		213,941
Net exercise of Series B’ redeemable convertible preferred stock warrants		$ 5,606
Conversion of redeemable convertible preferred stock into common stock (in shares)		16,828,119	16,828,119
Conversion of redeemable convertible preferred stock into common stock	147,028	$ 147,028	$ 17	147,011
Ending balance (in shares) at Jun. 30, 2021		0
Ending balance at Jun. 30, 2021		$ 0
Beginning balance (in shares) at Mar. 31, 2021			470,634
Beginning balance at Mar. 31, 2021	(156,436)		$ 0	240,032	33	(396,501)
Increase (Decrease) in Stockholders' Equity
Net loss	(8,494)					(8,494)
Unrealized gain (loss) on available-for-sale debt securities	(22)				(22)
Conversion of redeemable convertible preferred stock into common stock (in shares)		16,828,119	16,828,119
Conversion of redeemable convertible preferred stock into common stock	147,028	$ 147,028	$ 17	147,011
Net exercise of common stock warrants (in shares)			185
New issues (in shares)			6,900,000
Issuance of common stock upon initial public offering, net of issuance costs and underwriting discount of $11,813	105,487		$ 7	105,480
Issuance of common stock pursuant to stock option exercises (in shares)			95,770
Issuance of common stock pursuant to stock option exercises	4			4
Change in early exercise liability	(4)			(4)
Stock-based compensation	1,103			1,103
Ending balance (in shares) at Jun. 30, 2021			24,294,708
Ending balance at Jun. 30, 2021	$ 88,666		$ 24	493,626	11	(404,995)
Ending balance (in shares) at Sep. 30, 2021	0	0
Ending balance at Sep. 30, 2021	$ 0	$ 0
Increase (Decrease) in Stockholders' Equity
Net loss	(8,083)					(8,083)
Unrealized gain (loss) on available-for-sale debt securities	22				22
Issuance of common stock pursuant to stock option exercises (in shares)			13,190
Stock-based compensation	$ 1,107			1,107
Ending balance (in shares) at Sep. 30, 2021	24,307,898		24,307,898
Ending balance at Sep. 30, 2021	$ 81,712		$ 24	$ 494,733	$ 33	$ (413,078)

Condensed Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
Condensed Statements of Cash Flows - USD ($) $ in Thousands	Sep. 30, 2021	Sep. 30, 2020
Cash flows from operating activities
Net loss	$ (25,387)	$ (19,660)
Adjustments to reconcile net loss to net cash used in operating activities
Stock-based compensation expense	2,412	892
Depreciation	217	241
Amortization of debt discount and issuance costs	200	5,337
Non-cash interest expense	608	1,350
PIK interest incurred but not paid on term loan	0	(4,081)
Inventory write-downs	185	546
Realized loss from sale of short-term investments	0	15
Change in fair value of redeemable convertible preferred stock warrant liability	5,236	0
Change in fair value of derivative instrument	0	(149)
Loss on extinguishment of convertible notes	0	182
Changes in operating assets and liabilities
Accounts receivable	1,784	(2,038)
Inventory	(438)	896
Prepaid expenses and other assets	(2,227)	212
Accounts payable	259	45
Accrued liabilities	1,296	933
Other liabilities	0	317
Deferred rent	(519)	(223)
Net cash (used in) operating activities	(16,374)	(15,185)
Cash flows from investing activities
Acquisition of property and equipment	(230)	(16)
Proceeds from sale of short-term investments	0	6,300
Purchase of short-term investments	(85,012)	(7,005)
Net cash (used in) investing activities	(85,242)	(721)
Cash flows from financing activities
Issuance of common stock pursuant to stock option exercises	8	6
Proceeds from issuance of common stock in initial public offering, net of underwriter discount and commissions	109,089	0
Payment of deferred offering costs	(3,392)	0
Proceeds from issuance of redeemable convertible preferred stock, net of issuance costs	0	31,696
Repayment of debt	(4,090)	(42,121)
Proceeds from debt	0	54,047
Payment of debt issuance costs	0	(854)
Issuance of convertible notes, net of issuance costs (includes $0 and $11,867 from related parties in the nine months ended September 30, 2021 and 2020, respectively)	0	12,514
Net cash provided by financing activities	101,615	55,288
Net increase in cash and cash equivalents	(1)	39,382
Cash, cash equivalents and restricted cash
Beginning of the period	26,756	4,123
End of the period	26,755	43,505
Reconciliation of cash, cash equivalents and restricted cash to balance sheets:
Cash and cash equivalents	26,633	43,139
Restricted cash	122	366
Cash, cash equivalents and restricted cash in balance sheets	26,755	43,505
Supplemental disclosure of cash flow information:
Cash paid for interest	4,740	2,813
Supplemental disclosures of non-cash investing and financing information:
Net change in accrued liabilities from early exercise of options	4	0
Purchase of property and equipment included in accounts payable	97	0
Conversion of convertible notes and accrued interest into preferred stock	0	34,113
Extinguishment of derivative liability	0	6,239
Issuance of redeemable convertible preferred stock warrants in connection with the New Term Loan	0	550
Unpaid debt issuance costs included in accounts payable and accrued liabilities	$ 0	$ 94

Condensed Statements of Cash Flows (Parenthetical) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Statement of Cash Flows [Abstract]
Proceeds from related party debt	$ 0	$ 11,867

Condensed Statements of Redeemable Convertible Preferred Stock and Stockholders’ Equity (Deficit) (Parenthetical) $ in Thousands	3 Months Ended
	Jun. 30, 2021 USD ($)
Statement of Stockholders' Equity [Abstract]
Issuance costs and underwriting discount	$ 11,813

The Company	9 Months Ended
The Company	Sep. 30, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
The Company	The Company NeuroPace, Inc., or the Company, was incorporated in the state of Delaware on November 19, 1997. The Company is a commercial-stage medical device company that has developed the RNS System, the only commercially available brain-responsive neuromodulation system designed for treating medically refractory focal epilepsy by delivering personalized, real-time treatment at the seizure source. The Company began commercializing its products in the United States in 2014. Initial Public Offering On April 21, 2021, the Company’s registration statement on Form S-1 (File No. 333-254663) relating to its initial public offering, or IPO, of common stock became effective. The IPO closed on April 26, 2021, at which time the Company issued 6,900,000 shares of its common stock at a price of $17.00 per share, which included the issuance of shares in connection with the exercise by the underwriters of their option to purchase up to 900,000 additional shares. The Company received an aggregate of $117.3 million in gross proceeds, before underwriting discounts and commissions and offering costs, and approximately $105.5 million in net proceeds after deducting $8.2 million in underwriting discounts and commissions and $3.6 million in offering costs. Upon the closing of the IPO, all outstanding shares of the Company’s redeemable convertible preferred stock converted into 16,614,178 shares of common stock, warrants to purchase 346,823 shares of Series B’ convertible preferred stock net exercised to 213,941 shares of Series B’ convertible preferred stock and subsequently converted into common stock on a one-to-one basis, and warrants to purchase 219 shares of common stock net exercised to 185 shares of common stock. In connection with the completion of its IPO, on April 26, 2021, the Company’s certificate of incorporation was amended and restated to provide for 200,000,000 authorized shares of common stock with a par value of $0.001 per share and 10,000,000 authorized shares of preferred stock with a par value of $0.001 per share. Liquidity and Capital Resources The Company has incurred operating losses and negative cash flows from operations since its inception and has an accumulated deficit of $413.1 million as of September 30, 2021. For the nine months ended September 30, 2021 and 2020, the Company used $16.4 million and $15.2 million of cash in its operating activities, respectively. As of September 30, 2021, the Company had cash, cash equivalents and short-term investments of $123.3 million. Historically, the Company has funded its operations principally through the sales of its products, issuance of redeemable convertible preferred stock and debt financing. On April 26, 2021, the Company completed its IPO and received approximately $105.5 million in net proceeds after deducting underwriting discounts and commissions and offering costs. The Company’s condensed financial statements have been prepared on the basis of the Company continuing as a going concern for the next 12 months. Management believes that the Company’s cash, cash equivalents and short-term investments will allow the Company to continue its planned operations for at least the next 12 months from the date of the issuance of these unaudited interim condensed financial statements. In connection with the New Term Loan described in Note 6, the Company will need to be in compliance with a minimum annual net revenue covenant determined in accordance with generally accepted accounting principles beginning in the year ended December 31, 2021 of $43.0 million and maintain a minimum cash and cash equivalents balance of $5.0 million. If the Company cannot generate sufficient revenue in the future, the Company may not be in compliance with the annual net revenue covenant and the lender may call the debt resulting in the Company immediately needing additional funds. The COVID-19 pandemic is affecting business conditions in the industry in which the Company operates. Beginning in March 2020, the Company’s net sales were negatively impacted by the COVID-19 pandemic as hospitals delayed or canceled elective procedures. In response to the pandemic, many state and local governments in the U.S. issued orders that temporarily precluded elective procedures in order to conserve scarce health system resources. The decrease in hospital admission rates and elective surgeries reduced both the number of patients being evaluated for treatment with and demand for elective procedures using the Company's RNS System. A similar decrease occurred in the third quarter of 2021, as hospitals responded to new COVID-19 variants, including the Delta variant. The Company has taken necessary precautions to safeguard its employees, patients, customers, and other stakeholders from the COVID-19 pandemic, while maintaining business continuity to support its patients, customers and employees. The timing, extent and continuation of any increase in procedures, and any corresponding increase in sales of the Company’s products, and whether there could be a future decrease in the current level of procedures as a result of the COVID-19 pandemic or otherwise, remain uncertain and are subject to a variety of factors.

Summary of Significant Accounting Policies	9 Months Ended
Summary of Significant Accounting Policies	Sep. 30, 2021
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Basis of Presentation The unaudited interim condensed financial statements have been prepared in conformity with generally accepted accounting principles in the United States, or GAAP, as defined by the Financial Accounting Standards Board, or the FASB. Reverse Stock Split On August 18, 2020, the Company effected a 1-for-100 reverse stock split of its common stock and redeemable convertible preferred stock. The par value of the authorized stock was not adjusted as a result of the reverse stock split. On April 9, 2021, the Company effected a 1-for-2.6 reverse stock split of its common stock and redeemable convertible preferred stock. The par value of the authorized stock was not adjusted as a result of the reverse stock split. All issued and outstanding shares of common stock and redeemable convertible preferred stock and related per share amounts contained in the accompanying financial statements have been retroactively revised to reflect the combined effect of these reverse stock splits for all periods presented. Unaudited Interim Financial Information The condensed balance sheet as of December 31, 2020 was derived from the Company’s audited financial statements, but does not include all disclosures required by GAAP. The accompanying unaudited condensed financial statements as of September 30, 2021 and for the three and nine months ended September 30, 2021 and 2020, have been prepared by the Company, pursuant to the rules and regulations of the Securities and Exchange Commission, or the SEC, for interim financial statements. Certain information and footnote disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to such rules and regulations. However, the Company believes that the disclosures are adequate to make the information presented not misleading. Accordingly, these financial statements should be read in conjunction with the audited financial statements as of and for the year ended December 31, 2020 and notes thereto, included in the Company’s final prospectus for the IPO filed with the SEC pursuant to Rule 424(b)(4) on April 23, 2021, or the final prospectus. In the opinion of management, all adjustments, consisting only of normal recurring adjustments necessary for a fair statement of the Company’s condensed financial position as of September 30, 2021 and condensed results of operations for the three and nine months ended September 30, 2021 and 2020 and condensed cash flows for the nine months ended September 30, 2021 and 2020 have been made. The results of operations for the three and nine months ended September 30, 2021 are not necessarily indicative of the results of operations that may be expected for the year ending December 31, 2021. Use of Estimates The preparation of unaudited interim condensed financial statements in conformity with GAAP requires the Company to make estimates and assumptions that affect the amounts and disclosures reported in the financial statements. The Company uses significant judgment when making estimates related to the valuation of its common stock and related stock-based compensation, the valuation of deferred tax assets and related valuation allowances, provision for excess and obsolete inventories, the valuation of derivative financial instruments and redeemable convertible preferred stock warrant liability. The Company bases its estimates on historical experience and on various other assumptions that are believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Although these estimates are based on the Company’s knowledge of current events and actions it may undertake in the future, actual results may ultimately materially differ from these estimates and assumptions. Fair Value of Financial Instruments Carrying amounts of certain of the Company’s financial instruments, including cash equivalents, accounts receivable, accounts payable and accrued liabilities, approximate fair value because of the short-term nature of these instruments. Short-term investments comprise available-for-sale debt securities, which are carried at fair value. The Company believes that its borrowings bear interest at the prevailing market rates for instruments with similar characteristics; accordingly, the carrying value of this instrument approximates its fair value. Derivative instruments and the redeemable convertible preferred stock warrant liability are carried at fair value based on unobservable market inputs. The Company determines the fair value of financial and non-financial assets and liabilities using the fair value hierarchy which establishes three levels of inputs that may be used to measure fair value (see Note 3). Concentration of Credit Risk, and Other Risks and Uncertainties Financial instruments that potentially subject the Company to credit risk consist of cash and cash equivalents, short-term investments and accounts receivable to the extent of the amounts recorded on the balance sheet. The Company’s cash is invested in one major financial institution in the United States. Deposits in this financial institution may exceed federally insured limits. The Company’s cash equivalents are invested in money market funds. The Company’s accounts receivable are due from a variety of health care organizations in the United States. For the three and nine months ended September 30, 2021 and 2020, there were no customers that represented 10% or more of revenue. As of September 30, 2021 and December 31, 2020, no customer represented 10% or more of the Company’s accounts receivable. The Company is subject to certain risks, including that its devices may not be approved or cleared or continue to be approved or cleared for marketing by governmental authorities or be successfully marketed for expanded indications. There can be no assurance that the Company’s products will achieve widespread adoption in the marketplace, nor can there be any assurance that existing devices or any future devices can be developed or manufactured at an acceptable cost and speed and with appropriate performance characteristics. The Company is also subject to risks common to companies in the medical device industry, including, but not limited to, new technological innovations, dependence on healthcare providers to prescribe initial implants and replacements, dependence upon third-party payors to provide adequate coverage and reimbursement, dependence on key personnel, single-source suppliers and vendors in connection with the manufacture of its products, concentration of Level 4 CECs and epileptologists, obtaining, maintaining, protecting, enforcing, and defending intellectual property rights and proprietary technology, product liability claims, legal proceedings, and compliance with government regulations. The Company’s medical devices require approvals or clearances from the U.S. Food and Drug Administration, or the FDA, or international regulatory agencies. In addition, in order to continue the Company’s operations, compliance with various federal and state laws is required. If approvals or clearances were withdrawn by the FDA for the Company’s current products or if such approvals or clearances were denied or delayed for future products, product updates, or expanded indications for use, it would have a material adverse impact on the Company. Deferred Offering Costs The Company capitalizes, within other assets, certain legal, accounting and other third-party fees that are directly related to the Company’s in-process equity financings, including its IPO, until such financings are consummated. After consummation of the equity financing, these costs are recorded as a reduction of the proceeds received as a result of the offering. Should a planned equity financing be abandoned, terminated or significantly delayed, the deferred offering costs are immediately written off to operating expenses. As of December 31, 2020, $0.5 million of deferred offering costs were recorded on the condensed balance sheet. Upon closing the IPO, all deferred offering costs were charged against the proceeds from the IPO and recorded in stockholders equity (deficit) as a reduction of additional paid-in capital. As of September 30, 2021, there were no deferred offering costs recorded on the condensed balance sheet. Government Programs In May 2021, the Company was awarded a grant by the National Institutes of Health, or NIH, to support research of thalamocortical responsive neurostimulation for the treatment of Lennox-Gastaut Syndrome, a type of epilepsy. The award was issued for a five year period and has a total budget of over $9.3 million. Funding is approved for the first year beginning June 1, 2021 and provides for reimbursement of qualified direct and indirect expenses in the amount of $0.8 million. Approval of funds for years two through five is subject to the completion of certain milestones. For funds received under the NIH funding agreement, the Company recognizes a reduction in research and development expenses in an amount equal to the qualifying expenses incurred in each period up to the amount awarded by the NIH. Qualifying expenses incurred by the Company in advance of funding by the NIH are recorded within prepaid expenses and other current assets on the balance sheets. As of September 30, 2021, $57,000 of qualifying expenses have been incurred, all of which have been funded by the NIH. Net Loss per Share Attributable to Common Stockholders Basic net loss per common share is calculated by dividing the net loss attributable to common stockholders by the weighted-average number of shares of common stock outstanding during the period, without consideration of potentially dilutive securities. Diluted net loss per share is computed by dividing the net loss attributable to common stockholders by the weighted-average number of shares of common stock and potentially dilutive securities outstanding for the period. For purposes of the diluted net loss per share calculation, redeemable convertible preferred stock, stock options, common stock subject to repurchase related to early exercise of stock options, and convertible notes are considered to be potentially dilutive securities. Basic and diluted net loss attributable to common stockholders per share is presented in conformity with the two-class method required for participating securities, as the redeemable convertible preferred stock is considered a participating security because it participates in dividends with common stock. The Company also considers the shares issued upon the early exercise of stock options subject to repurchase to be participating securities, because holders of such shares have non-forfeitable dividend rights in the event a dividend is paid on common stock. The holders of redeemable convertible preferred stock and the holders of the shares issued upon early exercise of stock options subject to repurchase do not have a contractual obligation to share in the Company’s losses. As such, the net loss was attributed entirely to common stockholders. Because the Company has reported a net loss for all periods presented, diluted net loss per common share is the same as basic net loss per common share for those periods. Recent Accounting Pronouncements Recent Accounting Pronouncements Not Yet Adopted In February 2016, the FASB issued ASU No. 2016-02 (Topic 842), Leases. ASU 2016-02 requires lessees to apply a dual approach, classifying leases as either finance or operating leases based on the principle of whether or not the lease is effectively a financed purchase by the lessee. This classification will determine whether lease expense is recognized based on an effective interest method or on a straight-line basis over the term of the lease, respectively. A lessee is also required to record a right-of-use asset, or ROU, and a lease liability for all leases with a term of greater than 12 months regardless of their classification. This ASU provides a lessee with an option to not account for leases with a term of 12 month or less as leases in the scope of this ASU. This ASU will also require new qualitative and quantitative disclosures to help investors and other financial statement users better understand the amount, timing, and uncertainty of cash flows arising from leases. This ASU should be applied through a modified retrospective transition approach for leases existing at, or entered into after, the beginning of the earliest comparative period presented in the financial statements. In July 2018, the FASB issued ASU No. 2018-11, Leases (Topic 842): Targeted Improvements, which allows entities to elect an optional transition method where entities may continue to apply the existing lease guidance during the comparative periods and apply the new lease requirements through a cumulative effect adjustment in the period of adoption rather than in the earliest period presented. In June 2020, the FASB issued ASU 2020-05, Revenue from Contracts with Customers (Topic 606) and Leases (Topic 842): Effective Dates for Certain Entities, which delays the adoption dates for ASU 2016-02 for non-public entities to fiscal years beginning after December 15, 2021, and interim periods within fiscal years beginning after December 15, 2022. Early adoption is allowed. The Company will adopt Topic 842 effective January 1, 2022 using a modified retrospective method and will not restate comparative periods. Based on an analysis of its current portfolio of leases, the Company expects to recognize a ROU asset and lease liability for the Company’s facility lease. The Company is completing its evaluation of the key drivers, such as the discount rate, in the measurement of the ROU asset and lease liability and the quantitative impact that adoption will have on the financial statements in the future. In June 2016, the FASB issued ASU 2016-13, Financial Instruments- Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments, which amends existing guidance on the impairment of financial assets and adds an impairment model that is based on expected losses rather than incurred losses and requires an entity to recognize as an allowance its estimate of expected credit losses for its financial assets. An entity will apply this guidance through a cumulative-effect adjustment to retained earnings upon adoption (a modified-retrospective approach) while a prospective transition approach is required for debt securities for which an other-than-temporary impairment had been recognized before the effective date. For public business entities that meet the definition of an SEC filer, excluding entities eligible to be smaller reporting companies as defined by the SEC, adoption is effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. For SEC filers that are eligible to be smaller reporting companies and for all other entities, this ASU is effective for fiscal years beginning after December 15, 2022, and interim periods within those fiscal years. Early adoption is permitted. The Company is in the process of evaluating the impact of the adoption on its financial statements and related disclosures. In March 2020, the FASB issued ASU No. 2020-04, Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting. The amendments in ASU 2020-04 provide optional expedients and exceptions for applying generally accepted accounting principles to contracts, hedging relationships, and other transactions affected by reference rate reform if certain criteria are met. The amendments in this ASU are effective for all entities as of March 12, 2020 through December 31, 2022. An entity may elect to apply the amendments for contract modifications by Topic or Industry Subtopic as of any date from the beginning of an interim period that includes or is subsequent to March 12, 2020, or prospectively from the date that the financial statements are available to be issued. Once elected for a Topic or an Industry Subtopic, the amendments must be applied prospectively for all eligible contract modifications for that Topic or Industry Subtopic. The Company is currently evaluating the impact of the adoption of this ASU on the Company’s financial statements and related disclosures. In August 2020, the FASB issued ASU 2020-06, Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging-Contracts in Entity’s Own Equity (Subtopic 815-40): Accounting for Convertible Instruments and Contracts in an Entity’s Own Equity. This ASU simplifies the accounting for certain financial instruments with characteristics of liabilities and equity, including convertible instruments and contracts on an entity’s own equity. Specifically the ASU removes: i) major separation models required under GAAP and ii) certain settlement conditions that are required for equity contracts to qualify for the derivative scope exception, which will permit more equity contracts to qualify for the exception. For public business entities that meet the definition of an SEC filer, excluding entities eligible to be smaller reporting companies as defined by the SEC, this ASU is effective for interim and annual reporting periods beginning after December 15, 2021. For all other entities, the amendments are effective for fiscal years beginning after December 15, 2023, including interim periods within those fiscal years. Early adoption is permitted, but no earlier than fiscal years beginning after December 15, 2020, including interim periods within those fiscal years. The Company is currently evaluating the impact of the adoption of this ASU on the Company’s financial statements and related disclosures.

Fair Value Measurements

9 Months Ended

Sep. 30, 2021

Fair Value Disclosures [Abstract]

Fair Value Measurements

Fair Value MeasurementsThe Company measures certain financial assets and liabilities at fair value on a recurring basis. Fair value is an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As such, fair value is a market-based measurement that should be

determined based on assumptions that market participants would use in pricing an asset or a liability. A three-tier fair value hierarchy is established as a basis for considering such assumptions and for inputs used in the valuation methodologies in measuring fair value:

Level 1Quoted prices in active markets for identical assets or liabilities.

Level 2Observable inputs other than Level 1 prices such as quoted prices for similar assets or liabilities, quoted prices in markets that are not active, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities.

Level 3Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities.

The Company utilizes the market approach to measure fair value for its financial assets and liabilities. The market approach uses prices and other relevant information generated by market transactions involving identical or comparable assets or liabilities.

The following table summarizes the Company’s financial assets (cash equivalents, marketable securities and liabilities) at fair value as of September 30, 2021 (in thousands):


	Fair Value as of September 30, 2021		Basis for Fair Value Measurements
			(Level 1)		(Level 2)		(Level 3)
Assets:
Money market funds, included in cash and cash equivalents	$	25,312	$	25,312	$	—	$	—
Fixed income mutual funds, included in short-term investments	96,701		96,701		—		—
Total	$	122,013	$	122,013	$	—	$	—

There were no liabilities measured at fair value on a recurring and non-recurring basis as of September 30, 2021.

The following table summarizes the Company’s financial assets (cash equivalents, marketable securities and liabilities) at fair value as of December 31, 2020 (in thousands):


	Fair Value as of December 31, 2020		Basis for Fair Value Measurements
			(Level 1)		(Level 2)		(Level 3)
Assets:
Money market funds, included in cash and cash equivalents	$	5,062	$	5,062	$	—	$	—
Fixed income mutual funds, included in short-term investments	11,689		11,689		—		—
Total	$	16,751	$	16,751	$	—	$	—
Liabilities:
Redeemable convertible preferred stock warrant liability	369		—		—		369
Total	$	369	$	—	$	—	$	369

The money market funds are highly liquid and primarily invest in short-term fixed income securities issued by the U.S. government and U.S. government agencies. The Company’s available-for-sale investments comprise short-

term investments in fixed income mutual funds, which primarily consist of debt securities issued by the U.S. government and U.S. government agencies and corporate bonds and notes.

The following is a summary of the Company’s available-for-sale debt securities (in thousands):


	September 30,		December 31,
	2021		2020
Cost basis	$	96,668	$	11,656
Unrealized gain	33		33
Fair value	$	96,701	$	11,689

The following table sets forth a summary of the changes in the fair value of the Company’s Level 3 financial instruments (in thousands):


	Redeemable Convertible Preferred Stock Warrant Liability
Fair value as of January 1, 2021	$	369
Change in fair value included in other income (expense), net	5,236
Net exercise of redeemable convertible preferred stock warrants	$	(5,605)
Fair value as of September 30, 2021	$	—


	Derivative Instrument
Fair value as of January 1, 2020	$	4,719
Recognition of derivative instrument related to 2020 Convertible Notes	1,669
Change in fair value included in other income (expense), net	(149)
Extinguishment of derivative instrument	$	(6,239)
Fair value as of September 30, 2020	$	—

The fair value of the derivative instrument has been estimated at the date of inception and at the subsequent balance sheet date using a two-step approach to valuation, employing a probability-weighted scenario valuation method and then comparing the instrument’s value with-and-without the derivative features in order to estimate their combined fair value, using unobservable inputs, which are classified as Level 3 within the fair value hierarchy.

In August 2020, the derivative instrument was extinguished in connection with the issuance of Series B’ redeemable convertible preferred stock and conversion of all outstanding convertible notes and accrued unpaid interest into shares of Series B’ redeemable convertible preferred stock.

In determining the fair value of the redeemable convertible preferred stock warrant liability, the Company used the Black-Scholes option pricing model to estimate the fair value using unobservable inputs including the expected term, expected volatility, risk-free interest rate and dividend yield (see Note 8). There were no warrants outstanding for the purchase of redeemable convertible preferred stock as of September 30, 2021, as all such warrants were net exercised to shares of common stock upon the closing of the IPO.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Balance Sheet Components

9 Months Ended

Sep. 30, 2021

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Balance Sheet Components

Inventory

Inventories consist of the following (in thousands):


	September 30,		December 31,
	2021		2020
Raw materials	$	1,596	$	1,721
Work-in-process	1,467		1,487
Finished goods	4,099		3,701
Total	$	7,162	$	6,909

Property and Equipment, net

Property and equipment, net consists of the following (in thousands):


	September 30,		December 31,
	2021		2020
Machinery, equipment, furniture and fixtures	$	3,688	$	3,544
Computer equipment and software	2,912		2,730
Leasehold improvements	2,402		2,402
	9,002		8,676
Less: Accumulated depreciation	(8,378)		(8,161)
Property and equipment, net	$	624	$	515

Depreciation expense for the three months ended September 30, 2021 and 2020 was $0.1 million and $0.1 million, respectively. Depreciation expense for the nine months ended September 30, 2021 and 2020 was $0.2 million and $0.2 million, respectively.

Accrued Liabilities

Accrued liabilities consist of the following (in thousands):


	September 30,		December 31,
	2021		2020
Payroll and related expenses	$	5,618	$	4,565
Inventory-raw materials	340		636
Professional fees	164		279
Deferred rent, current	407		666
Clinical trials	—		107
Other	891		350
Total accrued liabilities	$	7,420	$	6,603

Commitments and Contingencies

9 Months Ended

Sep. 30, 2021

Commitments and Contingencies Disclosure [Abstract]

Commitments and Contingencies

Facility Lease

In August 2011, the Company entered into a non-cancelable operating lease for combined office and manufacturing facilities in Mountain View, California. The lease was scheduled to expire in April 2019 and was amended in May 2018 to extend it through June 2024. The terms of the facility lease provide for rental payments on

a graduated scale; however, rent expense is recognized on a straight-line basis over the lease term. The Company has an option to extend the lease for a period of five years, commencing on July 1, 2024 and expiring on June 30, 2029. In conjunction with the original lease agreement, the Company obtained a letter of credit for $0.9 million in lieu of a security deposit. In May 2019, the letter of credit was amended and reduced to $0.7 million. In June 2021, the letter of credit was amended and further reduced to $0.2 million.

Rental payments range from $2.9 million to $3.3 million per year over the extended term of the lease. In April 2020, the Company amended the lease agreement to defer 50.0% of the rental payment for May and June 2020 of $0.3 million. The deferred rental payments accrued interest at an annual rate of 8.0% starting from October 1, 2020 and were paid in three equal monthly installments commencing on April 1, 2021.

Rent expense for the three months ended September 30, 2021 and 2020 was $0.7 million and $0.7 million, respectively. Rent expense for the nine months ended September 30, 2021 and 2020 was $2.1 million and $2.0 million, respectively. As of September 30, 2021 and December 31, 2020, $1.4 million and $2.0 million was recorded as deferred rent expense, respectively.

The Company’s future payments under the non-cancellable operating lease (in thousands) are as follows:


	September 30, 2021
2021 (remaining three months)	$	777
2022	3,172
2023	3,267
2024	1,666
Total	$	8,882

Indemnifications

In the normal course of business, the Company enters into contracts and agreements that contain a variety of representations and warranties and may provide for indemnification of the counterparty. The Company’s exposure under these agreements is unknown because it involves claims that may be made against it in the future but have not yet been made. The Company may, from time to time, be subject to claims or be required to defend actions related to its indemnification obligations.

The Company indemnifies each of its directors and officers for certain events or occurrences, subject to certain limits, while the director or officer is or was serving at the Company’s request in such capacity, as permitted under Delaware law and in accordance with its certificate of incorporation and bylaws. The term of the indemnification period lasts as long as the director or officer may be subject to any proceeding arising out of acts or omissions of such individual in such capacity. The maximum amount of potential future indemnification is unlimited. The Company believes that the fair value of these indemnification obligations is minimal. Accordingly, the Company has not recognized any liabilities relating to these obligations as of September 30, 2021 and December 31, 2020.

Contingencies

From time to time, the Company may have certain contingent liabilities that arise in the ordinary course of business activities. The Company accrues a liability for such matters when it is probable that future expenditures will be made and such expenditures can be reasonably estimated. The Company determined that no accrual related to contingencies was required as of September 30, 2021 and December 31, 2020.

Legal Proceedings

The Company is, and from time to time may become, involved in legal proceedings. The Company may also pursue litigation to assert its legal rights and such litigation may be costly and divert the efforts and attention of its management and technical personnel which could adversely affect its business. Due to the uncertainty of litigation

and depending on the amount and the timing, an unfavorable resolution of some or all of such matters may materially affect our business, results of operations, financial position, or cash flows. The nature of the loss contingencies relating to claims that have been asserted against us are described below.

On October 18, 2021, three stockholders of the Company, James Jacoby, George Vachtsevanos, and Javier Echauz, filed a complaint in the United States District Court for the Northern District of California, entitled James Jacoby et al. v. NeuroPace, Inc., et al., Case No. 5:21-cv-8136, against the Company and its board of directors. The complaint alleges various claims related to the Company’s reverse stock splits and seeks, among other relief, damages and attorney’s fees. No estimates of possible losses or range of losses with respect to this action can be made at this time. The Company believes there is no merit to these allegations and intends to vigorously defend itself against this action.

Debt

9 Months Ended

Sep. 30, 2021

Debt Disclosure [Abstract]

Debt

2014 Term Loan

In November 2014, the Company entered into a Term Loan Agreement, as amended, with Capital Royalty Partners II L.P. and its affiliates for total borrowings of up to $40.0 million. As of December 31, 2019, $40.0 million had been funded under this Term Loan Agreement, or the Term Loan. The Term Loan bore interest at a rate of 12.5% per year. Payments under the Term Loan were to be made quarterly with payment dates fixed at the end of each calendar quarter.

The Term Loan was interest-only through September 30, 2019. Following the interest-only period, principal payments were to be made in equal installments at the end of the next four calendar quarters, with the final payment due on September 30, 2020. The Term Loan included a fee upon repayment of the loan equal to 5% of the aggregate principal amount being repaid. The Company ratably accreted the fee over the life of the loan.

In connection with the Term Loan, the Company paid total closing fees of $0.8 million and issued warrants to purchase 219 shares of its Series I redeemable convertible preferred stock at $1,866.80 per share. The initial fair value of the warrants was $0.3 million and resulted in a discount to the Term Loan, which was amortized to interest expense over the life of the loan using the effective interest method. Prior to 2020, these warrants were modified to be exercisable for 219 shares of common stock at $2.60 per share. Upon the closing of the IPO, warrants to purchase 219 shares of common stock net exercised to 185 shares of common stock.

In October 2019, the Term Loan Agreement was amended to extend the interest-only period through December 31, 2019. This amendment was accounted as a debt modification and the impact on the Term Loan’s effective interest rate was a decrease from 15.0% to 14.7%.

In February through June 2020, the Term Loan Agreement was amended to extend the interest-only period through June 30, 2020 and to allow the Company to pay interest entirely in kind by adding it to the aggregate principal of the loan. The Company paid $1.4 million in interest due on March 31, 2020 in kind and paid $1.4 million in interest due on June 30, 2020 in cash. The amendments were accounted as a debt modification and the Term Loan’s effective interest rate was changed within 14.7% to 14.2% with each amendment.

In September 2020, the Company repaid its entire obligation under the Term Loan amounting to $47.6 million, including principal of $44.1 million, interest of $1.3 million and fees of $2.2 million, using the proceeds from New Term Loan (as defined below). The repayment of the Term Loan was accounted for as a debt extinguishment, which resulted in an immaterial extinguishment loss.

2020 Term Loan

In September 2020, the Company entered into a new Term Loan Agreement with CRG Partners IV L.P. and its affiliates for total borrowings of up to $60.0 million, or the New Term Loan, and borrowed $50.0 million. The remaining $10.0 million of the New Term Loan will be available to the Company for borrowing until March 31, 2022 if the Company achieves a revenue-based milestone in 2021.

The New Term Loan bears interest at a rate of 12.5% per year. Payments under the New Term Loan are made quarterly with payment dates fixed at the end of each calendar quarter. The New Term Loan was interest-only through September 30, 2023, which could be extended through September 30, 2025 at the Company’s option if the Company completed its IPO on or prior September 30, 2023. In connection with closing the IPO, the Company extended the interest-only period to September 30, 2025. Following the interest-only period, principal payment is due in one installment on September 30, 2025. The New Term Loan includes a fee upon repayment of the loan equal to 10% of the aggregate principal amount being prepaid or repaid, or the backend fee. As of September 30, 2021, the New Term Loan had an annual effective interest rate of 15.66% per year.

The New Term Loan is collateralized by substantially all of the Company’s assets. The New Term Loan Agreement contains customary representations and warranties, covenants, events of default and termination provisions. The financial covenants require that the Company achieve minimum annual revenue thresholds commencing in 2021 and maintain a minimum balance of cash and cash equivalents (see Note 1).

The Company paid $1.0 million in fees to the lender and third parties which is reflected as a discount on the loan and is being accreted over the life of the loan using the effective interest method. Also, the Company issued warrants to the lender for a total of 346,823 shares of Series B’ redeemable convertible preferred stock. The warrants had a fair value of $0.6 million as of the issuance date, which was accounted for as debt issuance costs (see Note 8).

During the three months ended September 30, 2021 and 2020, the Company recorded interest expense related to deferred financing and debt issuance costs of the New Term Loan of $0.1 million and less than $0.1 million, respectively. During the nine months ended September 30, 2021 and 2020, the Company recorded interest expense related to deferred financing and debt issuance costs of the New Term Loan of $0.2 million and less than $0.1 million, respectively.

Interest expense on the New Term Loan was $1.9 million and $0.1 million during the three months ended September 30, 2021 and 2020, respectively. Interest expense on the New Term Loan was $5.5 million and $0.1 million during the nine months ended September 30, 2021 and 2020, respectively.

As of September 30, 2021, future minimum payments for the New Term Loan are as follows (in thousands):


	New Term Loan
2021 (remaining three months)	$	1,597
2022	6,337
2023	6,337
2024	6,354
2025	59,740
Total	80,365
Less: Unamortized debt discount and issuance cost	(1,229)
Less: Unaccreted backend fee	(4,190)
Less: Interest	(25,364)
New Term Loan	$	49,582

Paycheck Protection Program

In April 2020, the Company received $4.0 million from a federal Small Business Administration loan under the Paycheck Protection Program, or the PPP Loan. The note bore interest at 1.0% per year on the outstanding principal amount and had a maturity date 24 months from the date of the note. No payments were due for the six-month period beginning on the date of the note. Payments of principal and interest were due over the following 18 months. The Small Business Administration modified the PPP Loan such that monthly payments of principal and interest were due from September 2021 through April 2022. In April 2021, the Company repaid its entire obligation under

the PPP Loan amounting to $4.1 million, including principal of $4.0 million and interest of less than $0.1 million, using the proceeds from its IPO.

2019 and 2020 Convertible Notes

In March and September 2019, Company issued convertible notes to certain investors for aggregate proceeds of $21.3 million, or the 2019 Convertible Notes. In January and March 2020, the Company raised $7.1 million and $5.4 million, respectively, through the sale and issuance of additional convertible notes, or the 2020 Convertible Notes. The 2019 and 2020 Convertible Notes were subordinated to the Term Loan, bore interest on the outstanding principal amount at the rate of 8.0% per year, and had a maturity date of December 31, 2020.

Upon the consummation of an equity financing with aggregate proceeds to the Company of not less than $18 million, or the Qualified Financing, the outstanding principal balance of the 2019 and 2020 Convertible Notes and accrued but unpaid interest would convert into shares of capital stock issued in such Qualified Financing at a conversion price equal to 85% of the issuance price per share of such capital stock in such Qualified Financing. In the event the Company consummated, while the 2019 and 2020 Convertible Notes remained outstanding, an equity financing that did not constitute a Qualified Financing, then the majority holders had the option to treat such equity financing as a Qualified Financing. If the Company did not complete a Qualified Financing prior to the maturity date while the 2019 and 2020 Convertible Notes remained outstanding, the holders of the notes could elect to convert the outstanding principal and unpaid accrued interest into the Company’s Series A’ redeemable convertible preferred stock at a conversion price of $116.35 per share.

Upon the occurrence of a change of control, the 2019 and 2020 Convertible Notes would upon the election of the majority holders either (i) become due and payable upon the closing of such change of control in cash in an amount equal to (a) the outstanding principal amount plus any unpaid accrued interest, plus (b) a repayment premium equal to 100% of the outstanding principal amount, or (ii) be converted such that the outstanding principal balance of the notes and any unpaid accrued interest would convert into shares of the Company’s Series A’ redeemable convertible preferred stock at a conversion price equal to $116.35 per share.

The 2019 and 2020 Convertible Notes contained embedded derivative instruments, including automatic conversion into equity securities upon completion of a Qualified Financing, that were required to be bifurcated and accounted for separately as a single derivative instrument initially and subsequently measured at fair value with the change in fair value recorded in other income (expense), net in the statements of operations and comprehensive loss. The issuance date estimated fair values of the derivative instruments issued with the March and September 2019 notes were $4.1 million and $1.9 million, respectively, which were recorded as debt discounts. The issuance date estimated fair values of the derivative instruments issued with the January and March 2020 notes were $1.0 million and $0.7 million, respectively, which were recorded as debt discounts. In August 2020, the derivative instrument was extinguished in connection with the issuance of Series B’ redeemable convertible preferred stock.

The discount on the 2019 and 2020 Convertible Notes was amortized over the contractual term ending on December 31, 2020, using the effective interest method. The annual effective interest rate was estimated from 10.8% to 12.2% per year. The interest expense for the three months ended September 30, 2020 was $1.0 million, consisting of $0.2 million of contractual interest expense and $0.8 million amortization of debt discount arising from separation of the embedded derivative instrument. The interest expense for the nine months ended September 30, 2020 was $4.6 million, consisting of $1.4 million of contractual interest expense and $3.2 million amortization of debt discount arising from separation of the embedded derivative instrument.

For the nine months ended September 30, 2020, $10.3 million of convertible notes were issued to related parties. The interest expense on convertible notes issued to related parties for the three and nine months ended September 30, 2020 was $0.2 million and $1.3 million, respectively.

In connection with the sale and issuance of Series B’ redeemable convertible preferred stock all outstanding convertible notes were modified to remove the 15% discount on conversion. All outstanding convertible notes of $33.9 million and accrued unpaid interest of $2.5 million were converted into 8,379,410 shares of Series B’ redeemable convertible preferred stock at 100% of the preferred stock issuance price of $4.3423 per share.

The conversion of the 2019 Convertible Notes and 2020 Convertible Notes into shares of Series B' redeemable convertible preferred stock was accounted for as a debt extinguishment with $4.1 million extinguishment gain recognized as a deemed capital contribution to additional paid-in capital in the quarter ended September 30, 2020, as the holders of the notes were existing stockholders of the Company.

- Definition

The entire disclosure for information about short-term and long-term debt arrangements, which includes amounts of borrowings under each line of credit, note payable, commercial paper issue, bonds indenture, debenture issue, own-share lending arrangements and any other contractual agreement to repay funds, and about the underlying arrangements, rationale for a classification as long-term, including repayment terms, interest rates, collateral provided, restrictions on use of assets and activities, whether or not in compliance with debt covenants, and other matters important to users of the financial statements, such as the effects of refinancing and noncompliance with debt covenants.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-URI http://asc.fasb.org/topic&trid=2208564

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 1B
-Subparagraph (h)
-URI http://asc.fasb.org/extlink&oid=123466505&loc=SL123495323-112611

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 1C
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=123466505&loc=SL123495334-112611

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 1I
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123466505&loc=SL123495371-112611

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 1I
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=123466505&loc=SL123495371-112611

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(c))
-URI http://asc.fasb.org/extlink&oid=120395691&loc=d3e23780-122690

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 1B
-Subparagraph (g)
-URI http://asc.fasb.org/extlink&oid=123466505&loc=SL123495323-112611

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 1C
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123466505&loc=SL123495334-112611

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 1C
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123466505&loc=SL123495334-112611

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 1E
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123466505&loc=SL123495348-112611

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 1B
-URI http://asc.fasb.org/extlink&oid=123466505&loc=SL123495323-112611

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 1I
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123466505&loc=SL123495371-112611

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 1B
-Subparagraph (i)
-URI http://asc.fasb.org/extlink&oid=123466505&loc=SL123495323-112611

+ Details

Redeemable Convertible Preferred Stock

9 Months Ended

Sep. 30, 2021

Equity [Abstract]

Redeemable Convertible Preferred Stock

In August 2020, the Company amended its Certificate of Incorporation, pursuant to which the Company had two series of redeemable convertible preferred stock, designated as Series A’ and Series B’. In August 2020, the Company issued 7,599,720 shares of Series B’ redeemable convertible preferred stock at $4.3423 per share for gross proceeds of $33.0 million. In connection with the issuance of Series B’ redeemable convertible preferred stock, all outstanding convertible notes of $33.9 million and accrued unpaid interest of $2.5 million were converted into 8,379,410 shares of Series B’ redeemable convertible preferred stock at such price.

As of December 31, 2020, the redeemable convertible preferred stock comprised (in thousands, except per share and share amounts):


	Number of Shares Authorized	Number of Shares Issued and Outstanding	Carrying Amount		Liquidation Value		Original Issue Price
Series A’	1,651,154	635,048	$	73,340	$	36,945	$	58.1750
Series B’	59,106,232	15,979,130	$	68,082	$	190,810	$	4.3423
	60,757,386	16,614,178	$	141,422	$	227,755

On April 26, 2021, upon the closing of the Company’s IPO, all outstanding redeemable convertible preferred stock automatically converted into 16,614,178 shares of common stock. Prior to the closing of the Company’s IPO, the holders of redeemable convertible preferred stock had the following various rights and preferences:

Dividends

The holders of redeemable convertible preferred stock were entitled to receive dividends, out of any assets legally available therefore, prior and in preference to any declaration or payment of any dividend to the common stockholders, at the rate of $4.6540 per share per annum on each outstanding share of Series A’ redeemable convertible preferred stock and $0.3474 per share per annum on each outstanding share of Series B’ redeemable convertible preferred stock, payable when, as and if declared by the Board of Directors. Such dividends would not have been cumulative and if less than the full amount of dividends payable on the redeemable convertible preferred stock had been declared and paid, any such payments would have been made ratably among the holders of the redeemable convertible preferred stock in proportion to the total amount each holder would be entitled to receive if the full amount of dividends payable on the redeemable convertible preferred stock had been declared. No dividends have been declared to date.

Liquidation

In the event of any liquidation, dissolution or winding up of the Company, the holders of the Company’s Series B’ redeemable convertible preferred stock would have been entitled to receive, prior to any distribution of the Company’s assets to the holders of Series A’ redeemable convertible preferred stock and common stock, an amount per share equal to (i) as of and following August 19, 2020 (the “Initial Closing” of Series B’ redeemable convertible preferred stock), and prior to, at the Company’s election, the earlier of (a) the date the Company’s cash balance fell below $4.0 million and (b) March 31, 2022 (the “Deferred Closing”), 2.75 times $4.3423 per share for each share of Series B’ redeemable convertible preferred stock, and (ii) as of and following the date of the Deferred Closing, either (x) 2.75 times $4.3423 per share if the Company’s actual cash-burn between the Initial Closing and December 31, 2021 had been 110% or less of the Company’s business plan cash-burn for such time period as approved by the Board of Directors, or (y) otherwise 3 times $4.3423, for each share of Series B’ redeemable convertible preferred stock, plus declared but unpaid dividends.

If, upon the occurrence of such event, the assets and funds thus distributed among the holders of redeemable convertible preferred stock would have been insufficient to permit the payment to such holders of the full amounts, then the entire assets and funds of the Company legally available for distribution would have been distributed ratably among the holders of redeemable convertible preferred stock in proportion to the preferential amount each such holder was otherwise entitled to receive.

After full payment to the holders of Series B’ redeemable convertible preferred stock, the holders of Series A’ redeemable convertible preferred stock would have been entitled to receive, prior to any distribution of the Company’s assets to the holders of common stock, an amount per share equal to $58.1750 per share for each share of redeemable convertible preferred stock plus declared but unpaid dividends. If, upon the occurrence of such event, the assets and funds thus distributed among the holders of redeemable convertible preferred stock would have been insufficient to permit the payment to such holders of the full amounts, then the entire assets and funds of the Company legally available for distribution would have been distributed ratably among the holders of redeemable convertible preferred stock in proportion to the preferential amount each such holder was otherwise entitled to receive.

After the payment to the holders of redeemable convertible preferred stock of the full preferential amounts specified above, all of the remaining assets of the Company available for distribution to stockholders would have been distributed among the holders of Series B’ redeemable convertible preferred stock, Series A’ redeemable convertible preferred stock and common stock pro rata based on the number of shares of common stock held by each such holder, treating for this purpose all shares of redeemable convertible preferred stock as if converted to common stock prior to such liquidation, dissolution or winding up of the Company.

Conversion

The Company’s redeemable convertible preferred stock was convertible into shares of common stock at the option of a holder on a one-for-one basis with the conversion ratio subject to standard antidilutive adjustments, such as stock splits, stock dividends, combinations, subdivisions, recapitalizations or the like. The initial conversion price was $4.3423 and $58.1750 per share of Series B’ and Series A’ redeemable convertible preferred stock, respectively. Each share of Series A’ redeemable convertible preferred stock was convertible into shares of common stock immediately upon the date specified by written consent or written agreement of the holders of a majority of the outstanding shares of Series A’ redeemable convertible preferred stock. Each share of Series B’ redeemable convertible preferred stock was convertible into shares of common stock immediately upon (A) the date specified by written consent or written agreement of the holders of a majority of the outstanding shares of Series B’ redeemable convertible preferred stock and the Requisite Significant New Holders (as defined below) and (B) any firm commitment underwritten public offering approved by two new investors that had committed to the investment of an aggregate of $7,499,900 or more (each, a “Significant Investor”) in the Initial Closing and the Deferred Closing combined (such two Significant Investors, together, the “Requisite Significant New Holders”).

Voting Rights

The holders of redeemable convertible preferred stock had the right to one vote for each share of common stock into which such redeemable convertible preferred stock could then have been converted. With respect to such vote, the holder had full voting rights and powers equal to the voting rights and powers of the holders of common stock, would have been entitled to notice of any stockholders’ meeting in accordance with the bylaws of the Company, and would have been entitled to vote, together with holders of common stock, with respect to any question upon which holders of common stock have the right to vote.

Redemption and Balance Sheet Classification

The redeemable convertible preferred stock was recorded within mezzanine equity because, while it was not mandatorily redeemable, it would have become redeemable at the option of the holders upon the occurrence of certain deemed liquidation events that were considered not solely within the Company’s control.

Redeemable Convertible Preferred Stock Warrant Liability

9 Months Ended

Sep. 30, 2021

Other Liabilities Disclosure [Abstract]

Redeemable Convertible Preferred Stock Warrant Liability

On September 24, 2020, in connection with entering into the New Term Loan Agreement, the Company issued CRG Partners IV L.P. and its affiliates warrants to purchase 346,823 shares of Series B’ redeemable convertible preferred stock at an exercise price of $6.51339 per share, or the Series B’ Warrants, which was accounted as debt issuance costs.

The Series B’ Warrants would terminate at the earlier of the ten year anniversary from the issuance date, the closing of the Company’s IPO or Liquidation of the Company. These warrants had a net exercise provision under which their holders could, in lieu of payment of the exercise price in cash, surrender the warrant and receive a net amount of shares based on the fair market value of the Company’s stock at the time of exercise of the warrants after deduction of the aggregate exercise price. The Series B’ Warrants contained provisions for adjustment of the exercise price and number of shares issuable upon the exercise of warrants in the event of certain stock dividends, stock splits, reorganizations, reclassifications, and consolidations.

The fair value of the Series B’ Warrants on the date of issuance of $0.6 million was recorded as a debt discount. The Series B’ Warrants had a fair value of $0.4 million as of December 31, 2020. Upon the closing of the IPO, the Series B’ Warrants were net exercised to 213,941 shares of Series B’ convertible preferred stock and subsequently converted into common stock on a one-to-one basis. The Company remeasured the Series B’ Warrants to fair value upon the closing of the IPO, which was $5.6 million on April 26, 2021. The fair value of the Series B’ Warrants was valued as an intrinsic value of net exercised common stock on April 26, 2021, as according to Series B’ Warrants agreements the Series B’ Warrants were to be automatically exercised upon the IPO and the expected term of the Series B’ Warrants was zero immediately before the closing of the IPO. Upon the closing of the IPO, the redeemable convertible preferred stock warrant liability was reclassified to additional paid-in capital.

The change in fair value of $0 and $5.2 million during the three and nine months ended September 30, 2021, respectively, was recorded as a component of other income (expense), net in the statements of operations and comprehensive loss.

The redeemable convertible preferred stock warrant liability was valued using the following assumptions under the Black-Scholes option pricing model:


			December 31,
			2020
Stock price			$3.43
Expected term (in years)			9.7
Expected volatility			39.0%
Weighted average risk-free interest rate			0.91%
Dividend yield			—%

Common Stock

9 Months Ended

Sep. 30, 2021

Equity [Abstract]

Common Stock

The Company’s Certificate of Incorporation, as amended in April 2021, authorized the Company to issue 200,000,000 shares of $0.001 par value common stock.

The holders of common stock are entitled to receive dividends whenever funds and assets are legally available and when declared by the Board of Directors. As of September 30, 2021 and December 31, 2020, no dividends had been declared.

As of September 30, 2021 and December 31, 2020, the Company had reserved common stock for future issuance as follows:


	September 30,	December 31,
	2021	2020
Conversion of Series A’ redeemable convertible preferred stock	—	635,048
Conversion of Series B’ redeemable convertible preferred stock	—	15,979,130
Outstanding options under the 2009 Plan	—	6
Outstanding options under the 2020 Plan	—	2,835,265
Options available for future grant under the 2020 Plan	—	818,889
Outstanding options under the 2021 Plan	3,089,821	—
Options available for future grant under the 2021 Plan	2,713,254	—
Outstanding restricted stock units under the 2021 Plan	552,304	—
Common stock available for ESPP	580,000	—
Redeemable convertible preferred stock warrants issued and outstanding	—	346,823
Common stock warrants issued and outstanding	—	219
Total	6,935,379	20,615,380

- Definition

The entire disclosure for shareholders' equity comprised of portions attributable to the parent entity and noncontrolling interest, including other comprehensive income. Includes, but is not limited to, balances of common stock, preferred stock, additional paid-in capital, other capital and retained earnings, accumulated balance for each classification of other comprehensive income and amount of comprehensive income.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 13
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123467817&loc=SL123496158-112644

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 13
-URI http://asc.fasb.org/extlink&oid=123467817&loc=SL123496158-112644

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 14
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=123467817&loc=SL123496171-112644

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 14
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123467817&loc=SL123496171-112644

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=120397183&loc=d3e187085-122770

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 18
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=123467817&loc=SL123496189-112644

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 13
-Subparagraph (g)
-URI http://asc.fasb.org/extlink&oid=123467817&loc=SL123496158-112644

Reference 8: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-URI http://asc.fasb.org/topic&trid=2208762

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 18
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123467817&loc=SL123496189-112644

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 13
-Subparagraph (h)
-URI http://asc.fasb.org/extlink&oid=123467817&loc=SL123496158-112644

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 14
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123467817&loc=SL123496171-112644

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 18
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123467817&loc=SL123496189-112644

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 16
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123467817&loc=SL123496180-112644

Reference 14: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 13
-Subparagraph (i)
-URI http://asc.fasb.org/extlink&oid=123467817&loc=SL123496158-112644

Reference 15: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(e)(1))
-URI http://asc.fasb.org/extlink&oid=120395691&loc=d3e23780-122690

+ Details

Stock-Based Incentive Compensation Plans

9 Months Ended

Sep. 30, 2021

Share-based Payment Arrangement [Abstract]

Stock-Based Incentive Compensation Plans

A summary of stock option activity for the nine months ended September 30, 2021 is set forth below:


		Options Outstanding
	Shares Available for Grant	Number of Shares	Weighted-Average Exercise Price		Weighted Average Remaining Contractual Term (in Years)
Balances as of January 1, 2021	818,889	2,835,265	$	0.03	9.57
Authorized	2,900,000
Retired	(485,581)
Options granted	(577,144)	577,144	$	13.35
Options exercised		(265,498)	$	0.03
Options cancelled	57,090	(57,090)	$	0.64
Balances at September 30, 2021	2,713,254	3,089,821	$	2.50	9.07
Vested and exercisable at September 30, 2021		869,981	$	0.48	8.83
Vested and expected to vest at September 30, 2021		3,089,821	$	2.50	9.07

Early Exercise of Stock Options

The terms of the Company’s 2020 Stock Plan, or the 2020 Plan, and the 2021 Equity Incentive Plan, or the 2021 Plan, permit the exercise of options granted under the plans prior to vesting, subject to required approvals. The shares of common stock issued from the early exercise of unvested stock options are restricted and continue to vest over the original implied service period. The Company has the option to repurchase any unvested shares at the original purchase price upon any voluntary or involuntary termination. The shares purchased by the employees and non-employees pursuant to the early exercise of stock options are not deemed, for accounting purposes, to be outstanding until those shares vest. The cash received in exchange for exercised and unvested shares related to stock options granted is recorded as a liability for the early exercise of stock options in accrued liabilities on the accompanying balance sheet and will be transferred into common stock and additional paid-in capital as the shares vest. As of September 30, 2021 and December 31, 2020, there were 192,741 and 30,802 shares of common stock issued pursuant to early exercised options and subject to repurchase, respectively.

Employee Stock Purchase Plan

In April 2021, the Company adopted the 2021 Employee Stock Purchase Plan, or ESPP. The Company allows eligible employees to purchase shares of the Company's common stock through payroll deductions at a price equal to 85% of the lesser of the fair market value of the stock as of the first date or the ending date of each six month offering period. There were 580,000 shares of common stock reserved for issuance under the ESPP. As of September 30, 2021, total accumulated ESPP related employee payroll deductions amounted to $0.8 million, which were included within accrued payroll and related expenses in the consolidated balance sheets.

Restricted Stock Units

Activity with respect to restricted stock units was as follows:


	Number of Shares Underlying Outstanding Restricted Stock Units	Weighted Average Grant Date Fair Value
Unvested, January 1, 2021	—	$	—
Granted	566,050	$	23.49
Cancelled	(13,746)	$	23.79
Unvested, September 30, 2021	552,304	$	23.48

The Company recognized stock-based compensation as follows (in thousands):


	Three Months Ended September 30,				Nine Months Ended September 30,
	2021		2020		2021		2020
Cost of goods sold	$	93	$	5	$	134	$	14
Research and development	348		97		694		292
Selling, general and administrative	666		199		1,584		586
Total stock-based compensation	$	1,107	$	301	$	2,412	$	892

The above stock-based compensation expense related to the following equity-based awards (in thousands):


	Three Months Ended September 30,				Nine Months Ended September 30,
	2021		2020		2021		2020
Stock options and restricted stock units	$	714	$	301	$	1,839	$	892
ESPP	393		—		573		—
Total stock-based compensation	$	1,107	$	301	$	2,412	$	892

As of September 30, 2021, the total unrecognized stock-based compensation expense related to unvested stock options and restricted stock units was $17.3 million, which will be amortized on a straight-line basis over a weighted average remaining period of 3.5 years.

As of September 30, 2021, the Company had unrecognized stock-based compensation expense relating to the ESPP awards of approximately $0.3 million, which is expected to be recognized over a weighted-average period of 0.2 years.

Income Taxes	9 Months Ended
Income Taxes	Sep. 30, 2021
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The Company did not record a federal or state income tax provision or benefit for the three and nine months ended September 30, 2021 and 2020 as it has incurred net losses since inception. In addition, the net deferred tax assets generated from net operating losses are fully offset by a valuation allowance as the Company believes it is not more likely than not that the benefit will be realized. The Company accounts for the uncertainty in income taxes by utilizing a comprehensive model for the recognition, measurement, presentation and disclosure in financial statements of any uncertain tax positions that have been taken or are expected to be taken on an income tax return. There had been no changes in the estimated uncertain tax benefits recorded as of December 31, 2020.

- Definition

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 21
-URI http://asc.fasb.org/extlink&oid=121826272&loc=d3e32857-109319

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SAB Topic 11.C)
-URI http://asc.fasb.org/extlink&oid=122134291&loc=d3e330215-122817

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 17
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121826272&loc=d3e32809-109319

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB TOPIC 6.I.5.Q1)
-URI http://asc.fasb.org/extlink&oid=122134291&loc=d3e330036-122817

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 14
-URI http://asc.fasb.org/extlink&oid=121826272&loc=d3e32705-109319

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 270
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6424409&loc=d3e44925-109338

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-URI http://asc.fasb.org/topic&trid=2144680

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 30
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=6424122&loc=d3e41874-109331

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(h)(2))
-URI http://asc.fasb.org/extlink&oid=120395691&loc=d3e23780-122690

+ Details

Net Loss per Share Attributable to Common Stockholders

9 Months Ended

Sep. 30, 2021

Earnings Per Share [Abstract]

Net Loss per Share Attributable to Common Stockholders

The following table sets forth the computation of basic and diluted net loss per share attributable to common stockholders (in thousands, except for share and per share amounts):


	Three Months Ended September 30,				Nine Months Ended September 30,
	2021		2020		2021		2020
Numerator:
Net loss	$	(8,083)	$	(4,126)	$	(25,387)	$	(19,660)
Reduction of Series A' redeemable convertible preferred stock liquidation value	—		228		—		228
Net loss attributable to common stockholders	$	(8,083)	$	(3,898)	$	(25,387)	$	(19,432)
Denominator:
Weighted-average common stock outstanding used to compute basic and diluted net loss per share	24,101,399		202,408		14,061,958		202,382
Net loss per share attributable to common stockholders, basic and diluted	$	(0.34)	$	(19.26)	$	(1.81)	$	(96.02)

In connection with issuance of Series B’ redeemable convertible preferred stock, the Company amended the terms of the existing Series A’ redeemable convertible preferred stock and reduced the liquidation preference of Series A’ redeemable convertible preferred stock from $116.350 to $58.175. The reduction of Series A’ redeemable convertible preferred stock liquidation preference was accounted for as an extinguishment with $0.2 million recognized as extinguishment gain in accumulated deficit in the quarter ended September 30, 2020. The extinguishment gain reduced the net loss attributable to common stockholders for the three and nine months ended September 30, 2020.

The following potentially dilutive securities outstanding have been excluded from the computation of diluted weighted average shares outstanding because such securities have an antidilutive impact due to the Company’s net loss, in common stock equivalent shares:


	As of September 30,
	2021	2020
Redeemable convertible preferred shares	—	16,614,178
Options to purchase common stock	3,089,821	172,853
Unvested early exercised common stock options	192,741	57
Shares committed under ESPP	57,514	—
Unvested restricted stock units	552,304	—
Redeemable convertible preferred stock warrants	—	346,823
Total Shares	3,892,380	17,133,911

Related Parties	9 Months Ended
Related Parties	Sep. 30, 2021
Related Party Transactions [Abstract]
Related Parties	Related Parties Covidien Group S.a.r.l., an indirect wholly-owned subsidiary of Medtronic, plc, became a holder of more than five percent of the Company’s capital stock in August 2020. Pursuant to the terms of a cross-license with Medtronic, the Company made royalty payments of approximately $0.1 million during both the three months ended September 30, 2021 and 2020, and $0.3 million during both the nine months ended September 30, 2021 and 2020. Also see Note 6 for additional related party transactions related to the 2019 and 2020 Convertible Notes.

Summary of Significant Accounting Policies (Policies)	9 Months Ended
Summary of Significant Accounting Policies (Policies)	Sep. 30, 2021
Accounting Policies [Abstract]
Basis of Presentation and Unaudited Interim Financial Information	Basis of Presentation The unaudited interim condensed financial statements have been prepared in conformity with generally accepted accounting principles in the United States, or GAAP, as defined by the Financial Accounting Standards Board, or the FASB. Unaudited Interim Financial Information The condensed balance sheet as of December 31, 2020 was derived from the Company’s audited financial statements, but does not include all disclosures required by GAAP. The accompanying unaudited condensed financial statements as of September 30, 2021 and for the three and nine months ended September 30, 2021 and 2020, have been prepared by the Company, pursuant to the rules and regulations of the Securities and Exchange Commission, or the SEC, for interim financial statements. Certain information and footnote disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to such rules and regulations. However, the Company believes that the disclosures are adequate to make the information presented not misleading. Accordingly, these financial statements should be read in conjunction with the audited financial statements as of and for the year ended December 31, 2020 and notes thereto, included in the Company’s final prospectus for the IPO filed with the SEC pursuant to Rule 424(b)(4) on April 23, 2021, or the final prospectus. In the opinion of management, all adjustments, consisting only of normal recurring adjustments necessary for a fair statement of the Company’s condensed financial position as of September 30, 2021 and condensed results of operations for the three and nine months ended September 30, 2021 and 2020 and condensed cash flows for the nine months ended September 30, 2021 and 2020 have been made. The results of operations for the three and nine months ended September 30, 2021 are not necessarily indicative of the results of operations that may be expected for the year ending December 31, 2021.
Use of Estimates	Use of Estimates The preparation of unaudited interim condensed financial statements in conformity with GAAP requires the Company to make estimates and assumptions that affect the amounts and disclosures reported in the financial statements. The Company uses significant judgment when making estimates related to the valuation of its common stock and related stock-based compensation, the valuation of deferred tax assets and related valuation allowances, provision for excess and obsolete inventories, the valuation of derivative financial instruments and redeemable convertible preferred stock warrant liability. The Company bases its estimates on historical experience and on various other assumptions that are believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Although these estimates are based on the Company’s knowledge of current events and actions it may undertake in the future, actual results may ultimately materially differ from these estimates and assumptions.
Fair Value of Financial Instruments and Fair Value Measurements	Fair Value of Financial Instruments Carrying amounts of certain of the Company’s financial instruments, including cash equivalents, accounts receivable, accounts payable and accrued liabilities, approximate fair value because of the short-term nature of these instruments. Short-term investments comprise available-for-sale debt securities, which are carried at fair value. The Company believes that its borrowings bear interest at the prevailing market rates for instruments with similar characteristics; accordingly, the carrying value of this instrument approximates its fair value. Derivative instruments and the redeemable convertible preferred stock warrant liability are carried at fair value based on unobservable market inputs. The Company determines the fair value of financial and non-financial assets and liabilities using the fair value hierarchy which establishes three levels of inputs that may be used to measure fair value (see Note 3). The Company measures certain financial assets and liabilities at fair value on a recurring basis. Fair value is an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or a liability. A three-tier fair value hierarchy is established as a basis for considering such assumptions and for inputs used in the valuation methodologies in measuring fair value: Level 1Quoted prices in active markets for identical assets or liabilities. Level 2Observable inputs other than Level 1 prices such as quoted prices for similar assets or liabilities, quoted prices in markets that are not active, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. Level 3Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. The Company utilizes the market approach to measure fair value for its financial assets and liabilities. The market approach uses prices and other relevant information generated by market transactions involving identical or comparable assets or liabilities.
Concentration of Credit Risk, and Other Risks and Uncertainties	Concentration of Credit Risk, and Other Risks and Uncertainties Financial instruments that potentially subject the Company to credit risk consist of cash and cash equivalents, short-term investments and accounts receivable to the extent of the amounts recorded on the balance sheet. The Company’s cash is invested in one major financial institution in the United States. Deposits in this financial institution may exceed federally insured limits. The Company’s cash equivalents are invested in money market funds. The Company’s accounts receivable are due from a variety of health care organizations in the United States. For the three and nine months ended September 30, 2021 and 2020, there were no customers that represented 10% or more of revenue. As of September 30, 2021 and December 31, 2020, no customer represented 10% or more of the Company’s accounts receivable. The Company is subject to certain risks, including that its devices may not be approved or cleared or continue to be approved or cleared for marketing by governmental authorities or be successfully marketed for expanded indications. There can be no assurance that the Company’s products will achieve widespread adoption in the marketplace, nor can there be any assurance that existing devices or any future devices can be developed or manufactured at an acceptable cost and speed and with appropriate performance characteristics. The Company is also subject to risks common to companies in the medical device industry, including, but not limited to, new technological innovations, dependence on healthcare providers to prescribe initial implants and replacements, dependence upon third-party payors to provide adequate coverage and reimbursement, dependence on key personnel, single-source suppliers and vendors in connection with the manufacture of its products, concentration of Level 4 CECs and epileptologists, obtaining, maintaining, protecting, enforcing, and defending intellectual property rights and proprietary technology, product liability claims, legal proceedings, and compliance with government regulations. The Company’s medical devices require approvals or clearances from the U.S. Food and Drug Administration, or the FDA, or international regulatory agencies. In addition, in order to continue the Company’s operations, compliance with various federal and state laws is required. If approvals or clearances were withdrawn by the FDA for the Company’s current products or if such approvals or clearances were denied or delayed for future products, product updates, or expanded indications for use, it would have a material adverse impact on the Company.
Deferred Offering Costs	Deferred Offering CostsThe Company capitalizes, within other assets, certain legal, accounting and other third-party fees that are directly related to the Company’s in-process equity financings, including its IPO, until such financings are consummated. After consummation of the equity financing, these costs are recorded as a reduction of the proceeds received as a result of the offering. Should a planned equity financing be abandoned, terminated or significantly delayed, the deferred offering costs are immediately written off to operating expenses.
Government Programs	For funds received under the NIH funding agreement, the Company recognizes a reduction in research and development expenses in an amount equal to the qualifying expenses incurred in each period up to the amount awarded by the NIH. Qualifying expenses incurred by the Company in advance of funding by the NIH are recorded within prepaid expenses and other current assets on the balance sheets.
Net Loss per Share Attributable to Common Stockholders	Net Loss per Share Attributable to Common StockholdersBasic net loss per common share is calculated by dividing the net loss attributable to common stockholders by the weighted-average number of shares of common stock outstanding during the period, without consideration of potentially dilutive securities. Diluted net loss per share is computed by dividing the net loss attributable to common stockholders by the weighted-average number of shares of common stock and potentially dilutive securities outstanding for the period. For purposes of the diluted net loss per share calculation, redeemable convertible preferred stock, stock options, common stock subject to repurchase related to early exercise of stock options, and convertible notes are considered to be potentially dilutive securities. Basic and diluted net loss attributable to common stockholders per share is presented in conformity with the two-class method required for participating securities, as the redeemable convertible preferred stock is considered a participating security because it participates in dividends with common stock. The Company also considers the shares issued upon the early exercise of stock options subject to repurchase to be participating securities, because holders of such shares have non-forfeitable dividend rights in the event a dividend is paid on common stock. The holders of redeemable convertible preferred stock and the holders of the shares issued upon early exercise of stock options subject to repurchase do not have a contractual obligation to share in the Company’s losses. As such, the net loss was attributed entirely to common stockholders. Because the Company has reported a net loss for all periods presented, diluted net loss per common share is the same as basic net loss per common share for those periods.
Recent Accounting Pronouncements	Recent Accounting Pronouncements Recent Accounting Pronouncements Not Yet Adopted In February 2016, the FASB issued ASU No. 2016-02 (Topic 842), Leases. ASU 2016-02 requires lessees to apply a dual approach, classifying leases as either finance or operating leases based on the principle of whether or not the lease is effectively a financed purchase by the lessee. This classification will determine whether lease expense is recognized based on an effective interest method or on a straight-line basis over the term of the lease, respectively. A lessee is also required to record a right-of-use asset, or ROU, and a lease liability for all leases with a term of greater than 12 months regardless of their classification. This ASU provides a lessee with an option to not account for leases with a term of 12 month or less as leases in the scope of this ASU. This ASU will also require new qualitative and quantitative disclosures to help investors and other financial statement users better understand the amount, timing, and uncertainty of cash flows arising from leases. This ASU should be applied through a modified retrospective transition approach for leases existing at, or entered into after, the beginning of the earliest comparative period presented in the financial statements. In July 2018, the FASB issued ASU No. 2018-11, Leases (Topic 842): Targeted Improvements, which allows entities to elect an optional transition method where entities may continue to apply the existing lease guidance during the comparative periods and apply the new lease requirements through a cumulative effect adjustment in the period of adoption rather than in the earliest period presented. In June 2020, the FASB issued ASU 2020-05, Revenue from Contracts with Customers (Topic 606) and Leases (Topic 842): Effective Dates for Certain Entities, which delays the adoption dates for ASU 2016-02 for non-public entities to fiscal years beginning after December 15, 2021, and interim periods within fiscal years beginning after December 15, 2022. Early adoption is allowed. The Company will adopt Topic 842 effective January 1, 2022 using a modified retrospective method and will not restate comparative periods. Based on an analysis of its current portfolio of leases, the Company expects to recognize a ROU asset and lease liability for the Company’s facility lease. The Company is completing its evaluation of the key drivers, such as the discount rate, in the measurement of the ROU asset and lease liability and the quantitative impact that adoption will have on the financial statements in the future. In June 2016, the FASB issued ASU 2016-13, Financial Instruments- Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments, which amends existing guidance on the impairment of financial assets and adds an impairment model that is based on expected losses rather than incurred losses and requires an entity to recognize as an allowance its estimate of expected credit losses for its financial assets. An entity will apply this guidance through a cumulative-effect adjustment to retained earnings upon adoption (a modified-retrospective approach) while a prospective transition approach is required for debt securities for which an other-than-temporary impairment had been recognized before the effective date. For public business entities that meet the definition of an SEC filer, excluding entities eligible to be smaller reporting companies as defined by the SEC, adoption is effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. For SEC filers that are eligible to be smaller reporting companies and for all other entities, this ASU is effective for fiscal years beginning after December 15, 2022, and interim periods within those fiscal years. Early adoption is permitted. The Company is in the process of evaluating the impact of the adoption on its financial statements and related disclosures. In March 2020, the FASB issued ASU No. 2020-04, Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting. The amendments in ASU 2020-04 provide optional expedients and exceptions for applying generally accepted accounting principles to contracts, hedging relationships, and other transactions affected by reference rate reform if certain criteria are met. The amendments in this ASU are effective for all entities as of March 12, 2020 through December 31, 2022. An entity may elect to apply the amendments for contract modifications by Topic or Industry Subtopic as of any date from the beginning of an interim period that includes or is subsequent to March 12, 2020, or prospectively from the date that the financial statements are available to be issued. Once elected for a Topic or an Industry Subtopic, the amendments must be applied prospectively for all eligible contract modifications for that Topic or Industry Subtopic. The Company is currently evaluating the impact of the adoption of this ASU on the Company’s financial statements and related disclosures. In August 2020, the FASB issued ASU 2020-06, Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging-Contracts in Entity’s Own Equity (Subtopic 815-40): Accounting for Convertible Instruments and Contracts in an Entity’s Own Equity. This ASU simplifies the accounting for certain financial instruments with characteristics of liabilities and equity, including convertible instruments and contracts on an entity’s own equity. Specifically the ASU removes: i) major separation models required under GAAP and ii) certain settlement conditions that are required for equity contracts to qualify for the derivative scope exception, which will permit more equity contracts to qualify for the exception. For public business entities that meet the definition of an SEC filer, excluding entities eligible to be smaller reporting companies as defined by the SEC, this ASU is effective for interim and annual reporting periods beginning after December 15, 2021. For all other entities, the amendments are effective for fiscal years beginning after December 15, 2023, including interim periods within those fiscal years. Early adoption is permitted, but no earlier than fiscal years beginning after December 15, 2020, including interim periods within those fiscal years. The Company is currently evaluating the impact of the adoption of this ASU on the Company’s financial statements and related disclosures.

Fair Value Measurements (Tables)

9 Months Ended

Sep. 30, 2021

Fair Value Disclosures [Abstract]

Schedule of Assets and Liabilities, Measured at Fair Value

The following table summarizes the Company’s financial assets (cash equivalents, marketable securities and liabilities) at fair value as of September 30, 2021 (in thousands):


	Fair Value as of September 30, 2021		Basis for Fair Value Measurements
			(Level 1)		(Level 2)		(Level 3)
Assets:
Money market funds, included in cash and cash equivalents	$	25,312	$	25,312	$	—	$	—
Fixed income mutual funds, included in short-term investments	96,701		96,701		—		—
Total	$	122,013	$	122,013	$	—	$	—

There were no liabilities measured at fair value on a recurring and non-recurring basis as of September 30, 2021.

The following table summarizes the Company’s financial assets (cash equivalents, marketable securities and liabilities) at fair value as of December 31, 2020 (in thousands):


	Fair Value as of December 31, 2020		Basis for Fair Value Measurements
			(Level 1)		(Level 2)		(Level 3)
Assets:
Money market funds, included in cash and cash equivalents	$	5,062	$	5,062	$	—	$	—
Fixed income mutual funds, included in short-term investments	11,689		11,689		—		—
Total	$	16,751	$	16,751	$	—	$	—
Liabilities:
Redeemable convertible preferred stock warrant liability	369		—		—		369
Total	$	369	$	—	$	—	$	369

Schedule of Debt Securities, Available-for-sale

The following is a summary of the Company’s available-for-sale debt securities (in thousands):


	September 30,		December 31,
	2021		2020
Cost basis	$	96,668	$	11,656
Unrealized gain	33		33
Fair value	$	96,701	$	11,689

Schedule of Fair Value Liabilities Measured at Level 3

The following table sets forth a summary of the changes in the fair value of the Company’s Level 3 financial instruments (in thousands):


	Redeemable Convertible Preferred Stock Warrant Liability
Fair value as of January 1, 2021	$	369
Change in fair value included in other income (expense), net	5,236
Net exercise of redeemable convertible preferred stock warrants	$	(5,605)
Fair value as of September 30, 2021	$	—


	Derivative Instrument
Fair value as of January 1, 2020	$	4,719
Recognition of derivative instrument related to 2020 Convertible Notes	1,669
Change in fair value included in other income (expense), net	(149)
Extinguishment of derivative instrument	$	(6,239)
Fair value as of September 30, 2020	$	—

- Definition

Tabular disclosure of financial instruments measured at fair value, including those classified in shareholders' equity measured on a recurring or nonrecurring basis. Disclosures include, but are not limited to, fair value measurements recorded and the reasons for the measurements, level within the fair value hierarchy in which the fair value measurements are categorized and transfers between levels 1 and 2. Nonrecurring fair value measurements are those that are required or permitted in the statement of financial position in particular circumstances.

+ References + Details

Balance Sheet Components (Tables)

9 Months Ended

Sep. 30, 2021

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Schedule of Inventory, Current

Inventories consist of the following (in thousands):


	September 30,		December 31,
	2021		2020
Raw materials	$	1,596	$	1,721
Work-in-process	1,467		1,487
Finished goods	4,099		3,701
Total	$	7,162	$	6,909

Property, Plant and Equipment

Property and equipment, net consists of the following (in thousands):


	September 30,		December 31,
	2021		2020
Machinery, equipment, furniture and fixtures	$	3,688	$	3,544
Computer equipment and software	2,912		2,730
Leasehold improvements	2,402		2,402
	9,002		8,676
Less: Accumulated depreciation	(8,378)		(8,161)
Property and equipment, net	$	624	$	515

Schedule of Accrued Liabilities

Accrued liabilities consist of the following (in thousands):


	September 30,		December 31,
	2021		2020
Payroll and related expenses	$	5,618	$	4,565
Inventory-raw materials	340		636
Professional fees	164		279
Deferred rent, current	407		666
Clinical trials	—		107
Other	891		350
Total accrued liabilities	$	7,420	$	6,603

Commitments and Contingencies (Tables)

9 Months Ended

Sep. 30, 2021

Commitments and Contingencies Disclosure [Abstract]

Schedule of Minimum Annual Lease Commitments

The Company’s future payments under the non-cancellable operating lease (in thousands) are as follows:


	September 30, 2021
2021 (remaining three months)	$	777
2022	3,172
2023	3,267
2024	1,666
Total	$	8,882

Debt (Tables)

9 Months Ended

Sep. 30, 2021

Debt Disclosure [Abstract]

Schedule of Maturities of Long-term Debt

As of September 30, 2021, future minimum payments for the New Term Loan are as follows (in thousands):


	New Term Loan
2021 (remaining three months)	$	1,597
2022	6,337
2023	6,337
2024	6,354
2025	59,740
Total	80,365
Less: Unamortized debt discount and issuance cost	(1,229)
Less: Unaccreted backend fee	(4,190)
Less: Interest	(25,364)
New Term Loan	$	49,582

Redeemable Convertible Preferred Stock (Tables)

9 Months Ended

Sep. 30, 2021

Equity [Abstract]

Schedule of Temporary Equity

As of December 31, 2020, the redeemable convertible preferred stock comprised (in thousands, except per share and share amounts):


	Number of Shares Authorized	Number of Shares Issued and Outstanding	Carrying Amount		Liquidation Value		Original Issue Price
Series A’	1,651,154	635,048	$	73,340	$	36,945	$	58.1750
Series B’	59,106,232	15,979,130	$	68,082	$	190,810	$	4.3423
	60,757,386	16,614,178	$	141,422	$	227,755

Redeemable Convertible Preferred Stock Warrant Liability (Tables)

9 Months Ended

Sep. 30, 2021

Other Liabilities Disclosure [Abstract]

Schedule of Measurement Inputs

The redeemable convertible preferred stock warrant liability was valued using the following assumptions under the Black-Scholes option pricing model:


			December 31,
			2020
Stock price			$3.43
Expected term (in years)			9.7
Expected volatility			39.0%
Weighted average risk-free interest rate			0.91%
Dividend yield			—%

Common Stock (Tables)

9 Months Ended

Sep. 30, 2021

Equity [Abstract]

Schedule of Stock by Class

As of September 30, 2021 and December 31, 2020, the Company had reserved common stock for future issuance as follows:


	September 30,	December 31,
	2021	2020
Conversion of Series A’ redeemable convertible preferred stock	—	635,048
Conversion of Series B’ redeemable convertible preferred stock	—	15,979,130
Outstanding options under the 2009 Plan	—	6
Outstanding options under the 2020 Plan	—	2,835,265
Options available for future grant under the 2020 Plan	—	818,889
Outstanding options under the 2021 Plan	3,089,821	—
Options available for future grant under the 2021 Plan	2,713,254	—
Outstanding restricted stock units under the 2021 Plan	552,304	—
Common stock available for ESPP	580,000	—
Redeemable convertible preferred stock warrants issued and outstanding	—	346,823
Common stock warrants issued and outstanding	—	219
Total	6,935,379	20,615,380

- Definition

Tabular disclosure of an entity's stock, including par or stated value per share, number and dollar amount of share subscriptions, shares authorized, shares issued, shares outstanding, number and dollar amount of shares held in an employee trust, dividend per share, total dividends, share conversion features, par value plus additional paid in capital, the value of treasury stock and other information necessary to a fair presentation, and EPS information. Stock by class includes common, convertible, and preferred stocks which are not redeemable or redeemable solely at the option of the issuer. Includes preferred stock with redemption features that are solely within the control of the issuer and mandatorily redeemable stock if redemption is required to occur only upon liquidation or termination of the reporting entity. If more than one issue is outstanding, state the title of each issue and the corresponding dollar amount; dollar amount of any shares subscribed but unissued and the deduction of subscriptions receivable there from; number of shares authorized, issued, and outstanding.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=65888546&loc=d3e21300-112643

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(28))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=123467817&loc=d3e21553-112644

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 480
-SubTopic 10
-Section S99
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=122040564&loc=d3e177068-122764

Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=123467817&loc=d3e21538-112644

Reference 6: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=123467817&loc=d3e21521-112644

Reference 7: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(29))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Reference 8: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=123467817&loc=d3e21488-112644

Reference 9: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=120397183&loc=d3e187085-122770

Reference 10: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=123467817&loc=d3e21506-112644

Reference 11: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(27))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Reference 12: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=123467817&loc=d3e21484-112644

Reference 13: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=123467817&loc=d3e21475-112644

+ Details

Stock-Based Incentive Compensation Plans (Tables)

9 Months Ended

Sep. 30, 2021

Share-based Payment Arrangement [Abstract]

Summary of Stock Option Activity

A summary of stock option activity for the nine months ended September 30, 2021 is set forth below:


		Options Outstanding
	Shares Available for Grant	Number of Shares	Weighted-Average Exercise Price		Weighted Average Remaining Contractual Term (in Years)
Balances as of January 1, 2021	818,889	2,835,265	$	0.03	9.57
Authorized	2,900,000
Retired	(485,581)
Options granted	(577,144)	577,144	$	13.35
Options exercised		(265,498)	$	0.03
Options cancelled	57,090	(57,090)	$	0.64
Balances at September 30, 2021	2,713,254	3,089,821	$	2.50	9.07
Vested and exercisable at September 30, 2021		869,981	$	0.48	8.83
Vested and expected to vest at September 30, 2021		3,089,821	$	2.50	9.07

Schedule of Restricted Stock Units

Activity with respect to restricted stock units was as follows:


	Number of Shares Underlying Outstanding Restricted Stock Units	Weighted Average Grant Date Fair Value
Unvested, January 1, 2021	—	$	—
Granted	566,050	$	23.49
Cancelled	(13,746)	$	23.79
Unvested, September 30, 2021	552,304	$	23.48

Share-based Payment Arrangement, Expensed and Capitalized, Amount

The Company recognized stock-based compensation as follows (in thousands):


	Three Months Ended September 30,				Nine Months Ended September 30,
	2021		2020		2021		2020
Cost of goods sold	$	93	$	5	$	134	$	14
Research and development	348		97		694		292
Selling, general and administrative	666		199		1,584		586
Total stock-based compensation	$	1,107	$	301	$	2,412	$	892

The above stock-based compensation expense related to the following equity-based awards (in thousands):


	Three Months Ended September 30,				Nine Months Ended September 30,
	2021		2020		2021		2020
Stock options and restricted stock units	$	714	$	301	$	1,839	$	892
ESPP	393		—		573		—
Total stock-based compensation	$	1,107	$	301	$	2,412	$	892

Net Loss per Share Attributable to Common Stockholders (Tables)

9 Months Ended

Sep. 30, 2021

Earnings Per Share [Abstract]

Schedule of Earnings Per Share, Basic and Diluted

The following table sets forth the computation of basic and diluted net loss per share attributable to common stockholders (in thousands, except for share and per share amounts):


	Three Months Ended September 30,				Nine Months Ended September 30,
	2021		2020		2021		2020
Numerator:
Net loss	$	(8,083)	$	(4,126)	$	(25,387)	$	(19,660)
Reduction of Series A' redeemable convertible preferred stock liquidation value	—		228		—		228
Net loss attributable to common stockholders	$	(8,083)	$	(3,898)	$	(25,387)	$	(19,432)
Denominator:
Weighted-average common stock outstanding used to compute basic and diluted net loss per share	24,101,399		202,408		14,061,958		202,382
Net loss per share attributable to common stockholders, basic and diluted	$	(0.34)	$	(19.26)	$	(1.81)	$	(96.02)

Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share


	As of September 30,
	2021	2020
Redeemable convertible preferred shares	—	16,614,178
Options to purchase common stock	3,089,821	172,853
Unvested early exercised common stock options	192,741	57
Shares committed under ESPP	57,514	—
Unvested restricted stock units	552,304	—
Redeemable convertible preferred stock warrants	—	346,823
Total Shares	3,892,380	17,133,911

The Company (Details) - USD ($) $ / shares in Units, $ in Thousands		9 Months Ended
	Apr. 26, 2021	Sep. 30, 2021	Sep. 30, 2020	Apr. 30, 2021	Dec. 31, 2020
Finite-Lived Intangible Assets [Line Items]
Proceeds from issuance of common stock in initial public offering, net of underwriter discount and commissions		$ 109,089	$ 0
Common stock authorized (in shares)	200,000,000	200,000,000		200,000,000	74,636,348
Common stock par value (in dollars per share)	$ 0.001	$ 0.001		$ 0.001	$ 0.001
Shares authorized (in shares)	10,000,000	10,000,000			10,000,000
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001			$ 0.001
Accumulated deficit		$ 413,078			$ 387,691
Net cash used in operating activities		16,374	$ 15,185
Cash, cash equivalents, and short-term investments		$ 123,300
Minimum annual net revenue	$ 43,000
Minimum cash and cash equivalents required after completion of IPO	$ 5,000
Redeemable Convertible Preferred Stock Converted Into Common Stock
Finite-Lived Intangible Assets [Line Items]
Conversion of stock, shares issued (in shares)	16,614,178
Redeemable Convertible Preferred Stock Converted Into Warrants To Purchase Series B' Convertible Preferred Stock
Finite-Lived Intangible Assets [Line Items]
Conversion of stock, shares issued (in shares)	346,823
Redeemable Convertible Preferred Stock Converted Into Warrants Exercised To Series B' Convertible Preferred Stock
Finite-Lived Intangible Assets [Line Items]
Conversion of stock, shares issued (in shares)	213,941
Redeemable Convertible Preferred Stock Converted Into Warrants To Purchase Common Stock
Finite-Lived Intangible Assets [Line Items]
Conversion of stock, shares issued (in shares)	219
Redeemable Convertible Preferred Stock Converted Into Warrants Exercised To Common Stock
Finite-Lived Intangible Assets [Line Items]
Conversion of stock, shares issued (in shares)	185
IPO
Finite-Lived Intangible Assets [Line Items]
Number of shares issued in transaction (in shares)	6,900,000
Sale of stock (in dollars per share)	$ 17.00
Proceeds from issuance of common stock in initial public offering, net of underwriter discount and commissions	$ 117,300
Consideration received on transaction	105,500
Sale of stock, underwriting discounts	8,200
Sale of stock, offering costs	$ 3,600
Over-Allotment Option
Finite-Lived Intangible Assets [Line Items]
Number of shares issued in transaction (in shares)	900,000

Summary of Significant Accounting Policies (Details)			1 Months Ended	9 Months Ended
Summary of Significant Accounting Policies (Details)	Apr. 09, 2021	Aug. 18, 2020	May 31, 2021 USD ($)	Sep. 30, 2021 USD ($)	Dec. 31, 2020 USD ($)
Accounting Policies [Abstract]
Reverse stock split, conversion ratio	0.3846	0.0100
Deferred offering costs				$ 0	$ 484,000
Grant period (in years)			5 years
Research and development arrangement with federal government, total budget			$ 9,300,000
Compensation earned				800,000
Qualifying expenses incurred				$ 57,000

Fair Value Measurements - Narrative (Details) - USD ($)	Sep. 30, 2021	Dec. 31, 2020
Fair Value Disclosures [Abstract]
Fair value disclosure	$ 0	$ 369,000

Fair Value Measurements - Assets and Liabilities Measured at Fair Value (Details) - USD ($)	Sep. 30, 2021	Dec. 31, 2020
Assets:
Money market funds, included in cash and cash equivalents	$ 25,312,000	$ 5,062,000
Fixed income mutual funds, included in short-term investments	96,701,000	11,689,000
Total	122,013,000	16,751,000
Liabilities:
Redeemable convertible preferred stock warrant liability		369,000
Total	0	369,000
Fair Value, Inputs, Level 1
Assets:
Money market funds, included in cash and cash equivalents	25,312,000	5,062,000
Fixed income mutual funds, included in short-term investments	96,701,000	11,689,000
Total	122,013,000	16,751,000
Liabilities:
Redeemable convertible preferred stock warrant liability		0
Total		0
Fair Value, Inputs, Level 2
Assets:
Money market funds, included in cash and cash equivalents	0	0
Fixed income mutual funds, included in short-term investments	0	0
Total	0	0
Liabilities:
Redeemable convertible preferred stock warrant liability		0
Total		0
Fair Value, Inputs, Level 3
Assets:
Money market funds, included in cash and cash equivalents	0	0
Fixed income mutual funds, included in short-term investments	0	0
Total	$ 0	0
Liabilities:
Redeemable convertible preferred stock warrant liability		369,000
Total		$ 369,000

Fair Value Measurements - Available for Sale Debt Securities (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Fair Value Disclosures [Abstract]
Cost basis	$ 96,668	$ 11,656
Unrealized gain	33	33
Fair value	$ 96,701	$ 11,689

Fair Value Measurements - Changes in Fair Value of Level 3 Financial Instruments (Details) - Fair Value, Inputs, Level 3 - Derivative Instrument - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period	$ 369	$ 4,719
Recognition of derivative instrument related to 2020 Convertible Notes		1,669
Change in fair value included in other income (expense), net	5,236	(149)
Fair value, measurement with unobservable inputs reconciliation, recurring basis, liability, settlements	(5,605)	(6,239)
Balance at end of period	$ 0	$ 0

Balance Sheet Components - Inventory (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Raw materials	$ 1,596	$ 1,721
Work-in-process	1,467	1,487
Finished goods	4,099	3,701
Inventory	$ 7,162	$ 6,909

Balance Sheet Components - Property and Equipment (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 9,002		$ 9,002		$ 8,676
Less: Accumulated depreciation	(8,378)		(8,378)		(8,161)
Property and equipment, net	624		624		515
Depreciation	100	$ 100	217	$ 241
Machinery, equipment, furniture and fixtures
Property, Plant and Equipment [Line Items]
Property and equipment, gross	3,688		3,688		3,544
Computer equipment and software
Property, Plant and Equipment [Line Items]
Property and equipment, gross	2,912		2,912		2,730
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 2,402		$ 2,402		$ 2,402

Balance Sheet Components - Accrued Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020	Jun. 30, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Payroll and related expenses	$ 5,618	$ 4,565
Inventory-raw materials	340	636
Professional fees	164	279
Deferred rent, current	407	666	$ 300
Clinical trials	0	107
Other	891	350
Accrued Liabilities	$ 7,420	$ 6,603

Commitments and Contingencies - Additional Information (Details) - USD ($)	1 Months Ended	2 Months Ended	3 Months Ended		9 Months Ended
	May 31, 2018	Jun. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Jun. 30, 2021	Dec. 31, 2020	Oct. 01, 2020	May 31, 2019	Aug. 31, 2011
Loss Contingencies [Line Items]
Renewal term	5 years
Percent rental payment deferred		50.00%
Deferred rent, current		$ 300,000	$ 407,000		$ 407,000			$ 666,000
Deferred rent, interest rate, annual rate									8.00%
Operating leases, rent expense			700,000	$ 700,000	2,100,000	$ 2,000,000
Deferred rent credit			$ 1,400,000		$ 1,400,000			$ 2,000,000
Lease Facility
Loss Contingencies [Line Items]
Face amount							$ 200,000			$ 700,000	$ 900,000
Minimum
Loss Contingencies [Line Items]
Annual rental payments	$ 2,900,000
Maximum
Loss Contingencies [Line Items]
Annual rental payments	$ 3,300,000

Commitments and Contingencies - Operating Lease Maturity (Details) $ in Thousands	Sep. 30, 2021 USD ($)
Commitments and Contingencies Disclosure [Abstract]
2021 (remaining three months)	$ 777
2022	3,172
2023	3,267
2024	1,666
Total	$ 8,882

Debt - Additional Information (Details) - USD ($)				1 Months Ended								3 Months Ended		7 Months Ended	9 Months Ended		13 Months Ended
Debt - Additional Information (Details) - USD ($)	Apr. 26, 2021	Jun. 30, 2020	Mar. 31, 2020	Apr. 30, 2021	Sep. 30, 2020	Aug. 31, 2020	Mar. 31, 2020	Jan. 31, 2020	Sep. 30, 2019	Mar. 31, 2019	Nov. 30, 2014	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2021	Sep. 30, 2020	Apr. 30, 2021	Mar. 31, 2020	Dec. 31, 2020	Sep. 24, 2020	Jul. 01, 2020	Apr. 30, 2020	Dec. 31, 2019	Oct. 31, 2019
Debt Instrument [Line Items]
Interest rate					12.50%								12.50%			12.50%
Payment of debt issuance costs															$ 0	$ 854,000
Redeemable convertible preferred stock warrant liability												$ 0			$ 0				$ 369,000
Effective percentage												15.66%			15.66%
PIK interest incurred but not paid on term loan															$ 0	(4,081,000)
Repayment of debt															4,090,000	42,121,000
Proceeds from convertible debt															0	12,514,000
Proceeds from related party debt															0	11,867,000
Interest expense, related party												$ 0	$ 203,000		0	1,258,000
Gain (loss) on extinguishment of debt															0	$ (182,000)
Conversion of Series B’ redeemable convertible preferred stock
Debt Instrument [Line Items]
Conversion price (in dollars per share)						$ 4.3423
Convertible Debt
Debt Instrument [Line Items]
Interest rate					8.00%								8.00%			8.00%
Interest payment													$ 200,000			$ 1,400,000
Interest expense													1,000,000			4,600,000
Equity financing proceed threshold for conversion					$ 18,000,000								18,000,000			18,000,000
Threshold percentage of stock price trigger																		85.00%
Amortization of debt discount													800,000			3,200,000
Proceeds from related party debt																10,300,000
Interest expense, related party													$ 200,000			$ 1,300,000
Convertible Debt \| Conversion of Series A’ redeemable convertible preferred stock
Debt Instrument [Line Items]
Conversion price (in dollars per share)					$ 116.35								$ 116.35			$ 116.35
Repayment premium percent					100.00%								100.00%			100.00%
Convertible Debt \| Conversion of Series B’ redeemable convertible preferred stock
Debt Instrument [Line Items]
Conversion discount						15.00%
Convertible debt outstanding						$ 33,900,000
Interest payable						$ 2,500,000
Converted instrument, shares issued (in shares)						8,379,410
Share issuance price percentage						100.00%
Gain (loss) on extinguishment of debt													$ 4,100,000
Maximum \| Convertible Debt
Debt Instrument [Line Items]
Effective percentage																			12.20%
Minimum \| Convertible Debt
Debt Instrument [Line Items]
Effective percentage																			10.80%
Redeemable Convertible Preferred Stock Converted Into Warrants To Purchase Common Stock
Debt Instrument [Line Items]
Conversion of stock, shares issued (in shares)	219
Redeemable Convertible Preferred Stock Converted Into Warrants Exercised To Common Stock
Debt Instrument [Line Items]
Conversion of stock, shares issued (in shares)	185
2014 Term Loan
Debt Instrument [Line Items]
Face amount											$ 40,000,000												$ 40,000,000
Interest rate											12.50%
Redemption fee, percent											5.00%
Payment of debt issuance costs											$ 800,000
Effective percentage								14.70%	15.00%					15.00%							14.20%			14.70%
Interest payment			$ 1,400,000		$ 1,300,000
PIK interest incurred but not paid on term loan		$ 1,400,000
Repayment of debt					47,600,000
Repurchased face amount					44,100,000								44,100,000			$ 44,100,000
Payment for debt extinguishment					2,200,000
2014 Term Loan \| Series I Preferred Stock
Debt Instrument [Line Items]
Number of securities called by warrants or rights (in shares)											219
Exercise price of warrant (in dollars per share)											$ 1,866.8
Redeemable convertible preferred stock warrant liability											$ 300,000
2014 Term Loan \| Common stock warrants issued and outstanding
Debt Instrument [Line Items]
Number of securities called by warrants or rights (in shares)											219
Exercise price of warrant (in dollars per share)											$ 2.60
2020 Term Loans
Debt Instrument [Line Items]
Face amount					$ 50,000,000								$ 50,000,000			$ 50,000,000
Redemption fee, percent					10.00%								10.00%			10.00%
Unused borrowing capacity					$ 10,000,000								$ 10,000,000			$ 10,000,000
Amortization of debt issuance costs												100,000	100,000		200,000	100,000
Interest expense												$ 1,900,000	100,000		$ 5,500,000	100,000
2020 Term Loans \| Maximum
Debt Instrument [Line Items]
Face amount					60,000,000								60,000,000			60,000,000
2020 Term Loans \| Conversion of Series B’ redeemable convertible preferred stock
Debt Instrument [Line Items]
Exercise price of warrant (in dollars per share)																				$ 6.51339
Redeemable convertible preferred stock warrant liability	$ 5,600,000																		$ 400,000	$ 600,000
Backend fee					$ 1,000,000								$ 1,000,000			$ 1,000,000
Warrants outstanding (in shares)																				346,823
Paycheck Protection Program
Debt Instrument [Line Items]
Face amount																						$ 4,000,000
Interest rate																						1.00%
Interest payment																	$ 100,000
Repurchased face amount				$ 4,000,000													$ 4,000,000
Extinguishment of debt				$ 4,100,000
2019 Convertible Notes \| Convertible Debt
Debt Instrument [Line Items]
Proceeds from convertible debt														$ 21,300,000
Amortization of debt discount									$ 1,900,000	$ 4,100,000
2020 Convertible Notes \| Convertible Debt
Debt Instrument [Line Items]
Proceeds from convertible debt							$ 5,400,000	$ 7,100,000
Amortization of debt discount							$ 700,000	$ 1,000,000

Debt - Maturities of Debt (Details) - New Term Loan $ in Thousands	Sep. 30, 2021 USD ($)
Debt Instrument [Line Items]
2021 (remaining three months)	$ 1,597
2022	6,337
2023	6,337
2024	6,354
2025	59,740
Total	80,365
Less: Unamortized debt discount and issuance cost	(1,229)
Less: Unaccreted backend fee	(4,190)
Less: Interest	(25,364)
New Term Loan	$ 49,582

Redeemable Convertible Preferred Stock - Additional Information (Details)		1 Months Ended	9 Months Ended
	Apr. 26, 2021 shares	Aug. 31, 2020 USD ($) series $ / shares shares	Sep. 30, 2021 USD ($) vote $ / shares	Sep. 30, 2020 USD ($)	Dec. 31, 2020 $ / shares
Class of Stock [Line Items]
Proceeds from issuance of redeemable convertible preferred stock, net of issuance costs \| $			$ 0	$ 31,696,000
Redeemable convertible preferred stock, par value (in dollars per share) \| $ / shares			$ 0.001		$ 0.001
Redeemable Convertible Preferred Stock Converted Into Common Stock
Class of Stock [Line Items]
Conversion of stock, shares issued (in shares) \| shares	16,614,178
Conversion of Series B’ redeemable convertible preferred stock
Class of Stock [Line Items]
Number of series of preferred stock \| series		2
New issues (in shares) \| shares		7,599,720
Redemption price (in dollars per share) \| $ / shares		$ 4.3423
Proceeds from issuance of redeemable convertible preferred stock, net of issuance costs \| $		$ 33,000,000
Dividends per annum (in dollars per share) \| $ / shares			$ 0.3474
Cash balance trigger \| $			$ 4,000,000
Liquidation multiplier, before deferred closing date			2.75
Liquidation multiplier, between initial closing and December 31, 2021			2.75
Liquidation multiplier, all other scenarios			3
Redeemable convertible preferred stock, par value (in dollars per share) \| $ / shares			$ 4.3423		4.3423
Aggregate investment conversion threshold \| $			$ 7,499,900
Conversion of Series B’ redeemable convertible preferred stock \| Convertible Debt
Class of Stock [Line Items]
Convertible debt outstanding \| $		33,900,000
Interest payable \| $		$ 2,500,000
Converted instrument, shares issued (in shares) \| shares		8,379,410
Conversion of Series A’ redeemable convertible preferred stock
Class of Stock [Line Items]
Dividends per annum (in dollars per share) \| $ / shares			$ 4.6540
Redeemable convertible preferred stock, par value (in dollars per share) \| $ / shares					$ 58.1750
Redeemable Convertible Preferred Stock
Class of Stock [Line Items]
Number of votes per share \| vote			1

Redeemable Convertible Preferred Stock - Schedule of Stock (Details) - USD ($) $ / shares in Units, $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Class of Stock [Line Items]
Redeemable convertible preferred stock, shares authorized (in shares)	0	60,757,386
Redeemable convertible preferred stock, shares issued (in shares)	0	16,614,178
Redeemable convertible preferred stock, shares outstanding (in shares)	0	16,614,178
Carrying Amount	$ 0	$ 141,422
Liquidation Value	$ 0	$ 227,755
Original Issue Price (in dollars per share)	$ 0.001	$ 0.001
Conversion of Series A’ redeemable convertible preferred stock
Class of Stock [Line Items]
Redeemable convertible preferred stock, shares authorized (in shares)		1,651,154
Redeemable convertible preferred stock, shares issued (in shares)		635,048
Redeemable convertible preferred stock, shares outstanding (in shares)		635,048
Carrying Amount		$ 73,340
Liquidation Value		$ 36,945
Original Issue Price (in dollars per share)		$ 58.1750
Conversion of Series B’ redeemable convertible preferred stock
Class of Stock [Line Items]
Redeemable convertible preferred stock, shares authorized (in shares)		59,106,232
Redeemable convertible preferred stock, shares issued (in shares)		15,979,130
Redeemable convertible preferred stock, shares outstanding (in shares)		15,979,130
Carrying Amount		$ 68,082
Liquidation Value		$ 190,810
Original Issue Price (in dollars per share)	$ 4.3423	$ 4.3423

- Definition

Carrying amount, attributable to parent, of an entity's issued and outstanding stock which is not included within permanent equity. Temporary equity is a security with redemption features that are outside the control of the issuer, is not classified as an asset or liability in conformity with GAAP, and is not mandatorily redeemable. Includes any type of security that is redeemable at a fixed or determinable price or on a fixed or determinable date or dates, is redeemable at the option of the holder, or has conditions for redemption which are not solely within the control of the issuer. Includes stock with a put option held by an ESOP and stock redeemable by a holder only in the event of a change in control of the issuer.

+ References + Details

Redeemable Convertible Preferred Stock Warrant Liability - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended	9 Months Ended
	Apr. 26, 2021	Sep. 30, 2021	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020	Sep. 24, 2020
Class of Warrant or Right [Line Items]
Redeemable convertible preferred stock warrant liability		$ 0	$ 0		$ 369
Change in fair value			(5,236)	$ 0
Redeemable Convertible Preferred Stock Converted Into Warrants Exercised To Series B' Convertible Preferred Stock
Class of Warrant or Right [Line Items]
Conversion of stock, shares issued (in shares)	213,941
Conversion of Series B’ redeemable convertible preferred stock \| 2020 Term Loans
Class of Warrant or Right [Line Items]
Warrants outstanding (in shares)						346,823
Exercise price of warrant (in dollars per share)						$ 6.51339
Warrants term						10 years
Redeemable convertible preferred stock warrant liability	$ 5,600				$ 400	$ 600
Change in fair value		$ 0	$ 5,200

Redeemable Convertible Preferred Stock Warrant Liability - Schedule of Assumptions (Details)	Dec. 31, 2020 $ / shares
Stock price
Class of Warrant or Right [Line Items]
Measurement input	3.43
Expected term
Class of Warrant or Right [Line Items]
Measurement input	9.7
Expected volatility
Class of Warrant or Right [Line Items]
Measurement input	390.0
Weighted average risk-free interest rate
Class of Warrant or Right [Line Items]
Measurement input	0.0091
Dividend yield
Class of Warrant or Right [Line Items]
Measurement input	0

Common Stock (Details) - USD ($)	9 Months Ended	12 Months Ended
Common Stock (Details) - USD ($)	Sep. 30, 2021	Dec. 31, 2020	Apr. 30, 2021	Apr. 26, 2021
Class of Stock [Line Items]
Common stock authorized (in shares)	200,000,000	74,636,348	200,000,000	200,000,000
Common stock par value (in dollars per share)	$ 0.001	$ 0.001	$ 0.001	$ 0.001
Dividends declared cash	$ 0	$ 0
Common stock reserved for future issuance (in shares)	6,935,379	20,615,380
Conversion of Series A’ redeemable convertible preferred stock
Class of Stock [Line Items]
Common stock reserved for future issuance (in shares)	0	635,048
Conversion of Series B’ redeemable convertible preferred stock
Class of Stock [Line Items]
Common stock reserved for future issuance (in shares)	0	15,979,130
Outstanding options under the 2009 Plan
Class of Stock [Line Items]
Common stock reserved for future issuance (in shares)	0	6
Outstanding options under the 2020 Plan
Class of Stock [Line Items]
Common stock reserved for future issuance (in shares)	0	2,835,265
Options available for future grant under the 2020 Plan
Class of Stock [Line Items]
Common stock reserved for future issuance (in shares)	0	818,889
Outstanding options under the 2021 Plan
Class of Stock [Line Items]
Common stock reserved for future issuance (in shares)	3,089,821	0
Options available for future grant under the 2021 Plan
Class of Stock [Line Items]
Common stock reserved for future issuance (in shares)	2,713,254	0
Outstanding restricted stock units under the 2021 Plan
Class of Stock [Line Items]
Common stock reserved for future issuance (in shares)	552,304	0
Common stock available for ESPP
Class of Stock [Line Items]
Common stock reserved for future issuance (in shares)	580,000	0
Redeemable convertible preferred stock warrants issued and outstanding
Class of Stock [Line Items]
Common stock reserved for future issuance (in shares)	0	346,823
Common stock warrants issued and outstanding
Class of Stock [Line Items]
Common stock reserved for future issuance (in shares)	0	219

Stock-Based Incentive Compensation Plans - Summary of Stock Option Activity (Details)	9 Months Ended	12 Months Ended
	Sep. 30, 2021 $ / shares shares	Dec. 31, 2020 $ / shares shares
Number of Shares
Shares Available for Grant, beginning balance (in shares)	818,889
Number of shares, beginning balance (in shares)	2,835,265
Authorized (in shares)	2,900,000
Retired (in shares)	(485,581)
Options granted (in shares)	577,144
Options exercised (in shares)	(265,498)
Options cancelled (in shares)	57,090
Shares Available for Grant, ending balance (in shares)	2,713,254	818,889
Number of shares, ending balance (in shares)	3,089,821	2,835,265
Vested and exercisable (in shares)	869,981
Vested and expected to vest (in shares)	3,089,821
Weighted-Average Exercise Price
Beginning balance (in dollars per share) \| $ / shares	$ 0.03
Options granted (in dollar per share) \| $ / shares	13.35
Options exercised (in dollar per share) \| $ / shares	0.03
Options cancelled (in dollar per share) \| $ / shares	0.64
Ending balance (in dollars per share) \| $ / shares	2.50	$ 0.03
Vested and exercisable (in dollars per share) \| $ / shares	0.48
Vested and expected to vest (in dollars per share) \| $ / shares	$ 2.50
Weighted Average Remaining Contractual Term (in Years)
Balance	9 years 25 days	9 years 6 months 25 days
Exercisable	8 years 9 months 29 days
Vested and expected to vest	9 years 25 days

Stock-Based Incentive Compensation Plans - Summary of Restricted Stock Units (Details)	9 Months Ended
	Sep. 30, 2021 $ / shares shares
Number of Shares Underlying Outstanding Restricted Stock Units
Cancelled (in shares) \| shares	13,746
Weighted Average Grant Date Fair Value
Cancelled (in dollars per share) \| $ / shares	$ 23.79
Unvested restricted stock units
Number of Shares Underlying Outstanding Restricted Stock Units
Unvested, January 1, 2021 (in shares) \| shares	0
Granted (in shares) \| shares	566,050
Unvested, September 30, 2021 (in shares) \| shares	552,304
Weighted Average Grant Date Fair Value
Unvested, Weighted Average Grant Date Fair Value, beginning balance (in dollars per share) \| $ / shares	$ 0
Granted, Weighted Average Grant Date Fair Value (in dollars per share) \| $ / shares	23.49
Unvested, Weighted Average Grant Date Fair Value, ending balance (in dollars per share) \| $ / shares	$ 23.48

Stock-Based Incentive Compensation Plans - Additional Information (Details) - USD ($) $ in Millions	1 Months Ended	9 Months Ended
	Apr. 30, 2021	Sep. 30, 2021	Dec. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options, subject to repurchase (in shares)		192,741	30,802
ESPP discount percent	85.00%
Common stock reserved for future issuance (in shares)		6,935,379	20,615,380
Unrecognized stock-based compensation expense		$ 17.3
Period for recognition		3 years 6 months
2021 Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for future issuance (in shares)	580,000
Accumulated employee payroll deductions		$ 0.8
Period for recognition		2 months 12 days
Cost not yet recognized, amount		$ 0.3

Stock-Based Incentive Compensation Plans - Summary of Recognized Stock-based Compensation (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation	$ 1,107	$ 301	$ 2,412	$ 892
Stock options and restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation	714	301	1,839	892
ESPP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation	393	0	573	0
Cost of goods sold
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation	93	5	134	14
Research and development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation	348	97	694	292
Selling, general and administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation	$ 666	$ 199	$ 1,584	$ 586

Income Taxes (Details) - USD ($)	3 Months Ended		9 Months Ended
Income Taxes (Details) - USD ($)	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Income Tax Disclosure [Abstract]
Income tax expense	$ 0	$ 0	$ 0	$ 0

- Definition

Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

+ References + Details

Net Loss per Share Attributable to Common Stockholders - Computation of Basic and Diluted Net Loss Per Share (Details) - USD ($)	3 Months Ended						9 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Numerator:
Net loss	$ (8,083,000)	$ (8,494,000)	$ (8,810,000)	$ (4,126,000)	$ (8,793,000)	$ (6,741,000)	$ (25,387,000)	$ (19,660,000)
Reduction of Series A' redeemable convertible preferred stock liquidation value	0			228,000			0	228,000
Net loss attributable to common stockholders	$ (8,083,000)			$ (3,898,000)			$ (25,387,000)	$ (19,432,000)
Denominator:
Weighted-average common stock outstanding used to compute basic net loss per share (in shares)	24,101,399			202,408			14,061,958	202,382
Weighted-average common stock outstanding used to compute diluted net loss per share (in shares)	24,101,399			202,408			14,061,958	202,382
Net loss per share attributable to common stockholders, basic (in dollars per share)	$ (0.34)			$ (19.26)			$ (1.81)	$ (96.02)
Net loss per share attributable to common stockholders, diluted (in dollars per share)	$ (0.34)			$ (19.26)			$ (1.81)	$ (96.02)
Liquidation Value	$ 0						$ 0		$ 227,755,000
Extinguishment gain in accumulated deficit	$ 0			$ 228,000			$ 0	$ 228,000
Redeemable Convertible Preferred Stock
Numerator:
Reduction of Series A' redeemable convertible preferred stock liquidation value				200,000
Denominator:
Liquidation Value				58.175	$ 116.350			$ 58.175
Extinguishment gain in accumulated deficit				$ 200,000

Net Loss per Share Attributable to Common Stockholders - Schedule of Potentially Dilutive Securities Outstanding (Details) - shares	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total shares (in shares)	3,892,380	17,133,911
Redeemable convertible preferred shares
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total shares (in shares)	0	16,614,178
Options to purchase common stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total shares (in shares)	3,089,821	172,853
Unvested early exercised common stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total shares (in shares)	192,741	57
Shares committed under ESPP
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total shares (in shares)	57,514	0
Unvested restricted stock units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total shares (in shares)	552,304	0
Redeemable convertible preferred stock warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total shares (in shares)	0	346,823

Related Parties (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
Related Parties (Details) - USD ($) $ in Millions	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Affiliated Entity
Related Party Transaction [Line Items]
Payments for royalties	$ 0.1	$ 0.1	$ 0.3	$ 0.3