Outset Medical (OM) S-1 30 Nov 20 IPO registration Financial data

Cover

Cover	9 Months Ended
	Sep. 30, 2020
Cover [Abstract]
Document Type	S-1
Amendment Flag	false
Entity Registrant Name	Outset Medical, Inc.
Entity Central Index Key	0001484612
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Transition Period	false

Condensed Balance Sheets

Condensed Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 311,327	$ 36,926	$ 33,264
Short-term investments	32,888	33,152	109,518
Accounts receivable, net	7,082	3,914	1,088
Inventories	11,810	4,596	3,022
Prepaid expenses and other current assets	4,717	1,058	754
Total current assets	367,824	79,646	147,646
Restricted cash	33,311	743	151
Property and equipment, net	14,412	7,895	2,475
Operating lease right-of-use assets	8,498		451
Other assets	1,977	825	558
Total assets	426,022	88,366	151,130
Current liabilities:
Accounts payable	5,062	4,960	3,373
Accrued compensation and related benefits	10,850	6,956	3,837
Accrued expenses and other current liabilities	8,959	2,909	2,441
Accrued warranty liability	3,258	1,702	293
Deferred revenue, current	4,132	883	269
Operating lease liabilities, current	782		505
Term loan, current		7,500
Total current liabilities	33,043	24,910	10,213
Accrued interest, noncurrent	119	217	130
Deferred revenue, noncurrent	566	134	13
Operating lease liabilities, noncurrent	8,309	0	0
Redeemable convertible preferred stock warrant liability		4,285	8,085
Term loan, noncurrent	29,652	21,561	28,346
Finance lease liability			9
Total liabilities	71,689	51,107	46,796
Commitments and contingencies
Stockholders' equity (deficit):
Preferred stock
Common stock	42	1	1
Additional paid-in capital	816,306	357
Accumulated other comprehensive income	1	22	(60)
Accumulated deficit	(462,016)	(372,567)	(287,891)
Total stockholders' equity (deficit)	354,333	(372,187)	(287,950)
Redeemable convertible preferred stock		409,446	392,284
Total liabilities, redeemable convertible preferred stock and stockholders' equity (deficit)	$ 426,022	88,366	151,130
Previously Reported [Member]
Current assets:
Other assets		82
Redeemable Convertible Preferred Stock
Stockholders' equity (deficit):
Redeemable convertible preferred stock		$ 409,446	$ 392,284

Condensed Balance Sheets (Paren

Condensed Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019	Dec. 31, 2018
Allowance for doubtful accounts		$ 59	$ 0
Redeemable convertible preferred stock, shares authorized		154,592,485	154,592,485
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.001	$ 0.001	$ 0.001
Common stock, shares authorized	300,000,000	240,000,000	150,000,000
Common stock, shares issued	42,701,000	922,078	789,100
Common stock, shares outstanding	42,701,000	922,078	789,100
Redeemable Convertible Preferred Stock
Redeemable convertible preferred stock, par value	$ 0.001	$ 0.001	$ 0.001
Redeemable convertible preferred stock, shares authorized	0	154,592,485	161,888,418
Redeemable convertible preferred stock, shares issued	0	147,214,244	147,214,244
Redeemable convertible preferred stock, shares outstanding	0	147,214,244	147,214,244

Condensed Statements of Operati

Condensed Statements of Operations - USD ($) $ in Thousands	9 Months Ended		12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019	Dec. 31, 2018
Revenue:
Revenue	$ 32,688	$ 7,993	$ 15,078	$ 2,007
Cost of revenue:
Cost of revenue	46,142	23,015	32,880	8,122
Gross profit	(13,454)	(15,022)	(17,802)	(6,115)
Operating expenses:
Research and development	21,066	16,698	23,327	22,916
Sales and marketing	29,870	13,376	20,259	11,279
General and administrative	21,462	6,641	8,919	6,253
Total operating expenses	72,398	36,715	52,505	40,448
Loss from operations	(85,852)	(51,737)	(70,307)	(46,563)
Interest income and other income (expense), net	524	2,111	2,485	1,709
Interest expense	(2,461)	(3,237)	(4,257)	(4,639)
Change in fair value of redeemable convertible preferred stock warrant liability	(93)	4,030	3,800	(262)
Loss on extinguishment of term loan	(1,567)
Loss before provision for income taxes	(89,449)	(48,833)	(68,279)	(49,755)
Provision for income taxes		20	20	25
Net loss	(89,449)	(48,853)	(68,299)	(49,780)
Adjustment to redemption value on redeemable convertible preferred stock			(134,760)	(23,300)
Gain on extinguishment of redeemable convertible preferred stock		117,598	117,597
Net loss attributable to common stockholders	(47,281)	(66,015)	(85,462)	(73,080)
Net loss attributable to common stockholders, basic and diluted	$ (47,281)	$ (66,015)	$ (85,462)	$ (73,080)
Net loss per share attributable to common stockholders, basic and diluted	$ (6.30)	$ (78.77)	$ (99.58)	$ (100.75)
Weighted average shares used in computing net loss per share attributable to common stockholders, basic and diluted	7,508,000	838,000	858,254	725,337
Product Revenue
Revenue:
Revenue	$ 26,435	$ 7,501	$ 13,750	$ 1,749
Cost of revenue:
Cost of revenue	42,118	18,950	27,164	7,806
Service Revenue
Revenue:
Revenue			1,328	258
Cost of revenue:
Cost of revenue			5,716	316
Service and Other Revenue
Revenue:
Revenue	6,253	492	$ 1,328	$ 258
Cost of revenue:
Cost of revenue	$ 4,024	$ 4,065

Condensed Statements of Compreh

Condensed Statements of Comprehensive Loss - USD ($) $ in Thousands	9 Months Ended		12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019	Dec. 31, 2018
Statement of Comprehensive Income [Abstract]
Net loss	$ (89,449)	$ (48,853)	$ (68,299)	$ (49,780)
Other comprehensive (loss) income:
Unrealized (loss) gain on available-for-sale securities	(21)	102	82	(37)
Comprehensive loss	$ (89,470)	$ (48,751)	$ (68,217)	$ (49,817)

Condensed Statement of Redeemab

Condensed Statement of Redeemable Convertible Preferred Stock and Stockholders' Equity (Deficit) - USD ($)	Total	IPO	Redeemable Convertible Preferred Stock	Redeemable Convertible Preferred StockIPO	Common Stock	Common StockIPO	Additional Paid-in Capital	Additional Paid-in CapitalIPO	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Temporary Equity, Beginning Balance at Dec. 31, 2017			$ 234,418,000
Temporary Equity, Beginning Balance (shares) at Dec. 31, 2017			103,862,065
Temporary Equity, Issuance of Series D redeemable convertible preferred stock, net of issuance costs of $259			$ 134,567,000
Temporary Equity, Issuance of Series D redeemable convertible preferred stock, net of issuance costs of $259 (Shares)			43,352,179
Temporary equity, Adjustment to redemption value on redeemable convertible preferred stock			$ 23,299,000
Temporary Equity, Ending Balance at Dec. 31, 2018	$ 392,284,000		$ 392,284,000
Temporary Equity, Ending Balance (shares) at Dec. 31, 2018			147,214,244
Beginning Balance at Dec. 31, 2017	(215,937,000)				$ 1,000				$ (23,000)	$ (215,915,000)
Beginning Balance (shares) at Dec. 31, 2017					677,750
Adjustment to redemption value on redeemable convertible preferred stock	(23,299,000)						$ (1,103,000)			(22,196,000)
Stock option exercises	315,000						315,000
Stock option exercises (shares)					111,350
Stock-based compensation	788,000						788,000
Unrealized gain on available-for-salesecurities	(37,000)								(37,000)
Net loss	(49,780,000)									(49,780,000)
Ending Balance at Dec. 31, 2018	(287,950,000)				$ 1,000				(60,000)	(287,891,000)
Ending Balance (shares) at Dec. 31, 2018					789,100
Temporary Equity, Gain on extinguishment of redeemable convertible preferred stock			$ (117,417,000)
Temporary Equity, Costs to adjust the redemption value on redeemable convertible preferred stock			(181,000)
Temporary equity, Adjustment to redemption value on redeemable convertible preferred stock			134,760,000
Temporary Equity, Ending Balance at Sep. 30, 2019			$ 409,446,000
Temporary Equity, Ending Balance (shares) at Sep. 30, 2019			147,214,244
Adjustment to redemption value on redeemable convertible preferred stock	(134,760,000)						(966,000)			(133,794,000)
Stock option exercises	254,000						254,000
Stock option exercises (shares)					84
Common stock warrant exercises	76,000						76,000
Common stock warrant exercises (shares)					9
Stock-based compensation	636,000						636,000
Unrealized gain on available-for-salesecurities	102,000								102,000
Gain on extinguishment of redeemable convertible preferred stock	117,417,000									117,417,000
Costs to adjust the redemption value on redeemable convertible preferred stock	0				$ 0		0		0	0
Net loss	(48,853,000)									(48,853,000)
Ending Balance at Sep. 30, 2019	(353,078,000)				$ 1,000				42,000	(353,121,000)
Ending Balance (shares) at Sep. 30, 2019					882
Temporary Equity, Beginning Balance at Dec. 31, 2018	392,284,000		$ 392,284,000
Temporary Equity, Beginning Balance (shares) at Dec. 31, 2018			147,214,244
Temporary Equity, Gain on extinguishment of redeemable convertible preferred stock			$ (117,417,000)
Temporary Equity, Costs to adjust the redemption value on redeemable convertible preferred stock			(181,000)
Temporary equity, Adjustment to redemption value on redeemable convertible preferred stock			134,760,000
Temporary Equity, Ending Balance at Dec. 31, 2019	409,446,000		$ 409,446,000
Temporary Equity, Ending Balance (shares) at Dec. 31, 2019			147,214,244
Beginning Balance at Dec. 31, 2018	(287,950,000)				$ 1,000				(60,000)	(287,891,000)
Beginning Balance (shares) at Dec. 31, 2018					789,100
Adjustment to redemption value on redeemable convertible preferred stock	(134,760,000)						(966,000)			(133,794,000)
Stock option exercises	364,000						364,000
Stock option exercises (shares)					124,118
Common stock warrant exercises	76,000						76,000
Common stock warrant exercises (shares)					8,860
Stock-based compensation	883,000						883,000
Unrealized gain on available-for-salesecurities	82,000								82,000
Gain on extinguishment of redeemable convertible preferred stock	117,417,000									117,417,000
Net loss	(68,299,000)									(68,299,000)
Ending Balance at Dec. 31, 2019	(372,187,000)				$ 1,000		357,000		22,000	(372,567,000)
Ending Balance (shares) at Dec. 31, 2019					922,078
Temporary Equity, Issuance of Series D redeemable convertible preferred stock, net of issuance costs of $259			$ 126,758,000
Temporary Equity, Issuance of Series D redeemable convertible preferred stock, net of issuance costs of $259 (Shares)			57,782,000
Temporary Equity, Issuance of common stock on settlement of accrued dividend			$ (41,763,000)
Temporary Equity, Deemed dividend on settlement of accrued dividend			(42,530,000)
Temporary equity, Adjustment to redemption value on redeemable convertible preferred stock			$ 362,000
Temporary Equity, Cash exercises of Series C redeemable convertible preferred stock warrants (shares)			1,655,000
Temporary Equity, Cash exercises of Series C redeemable convertible preferred stock warrants			$ 4,288,000
Temporary Equity, Ending Balance (shares) at Sep. 30, 2020			0
Net of issuance costs	0				$ 0		0		0	0
Issuance of common stock on settlement of accrued dividend	41,763,000				5,000		41,758,000
Issuance of common stock on settlement of accrued dividend (shares)					4,850
Deemed dividend on settlement of accrued dividend	42,530,000						42,530,000
Adjustment to redemption value on redeemable convertible preferred stock	(362,000)						(362,000)
Issuance of common stock upon net exercises of Series B redeemable convertible preferred stock warrants	0				$ 0		0		0	0
Issuance of common stock upon net exercises of Serie B redeemable convertible preferred stock warrants (shares)					65
Conversion of Series A redeemable convertible preferred stock warrants to common stock warrants	1,252,000						1,252,000
Conversion of redeemable convertible preferred stock to common stock upon initial public offering	456,561,000			$ (456,561,000)	$ 26,000		456,535,000
Conversion of redeemable convertible preferred stock to common stock upon initial public offering (shares)				(206,651,000)	26,167
Issuance of common stock upon initial public offering, net of issuance costs		$ 254,805,000				$ 10,000		$ 254,795,000
Issuance of common stock upon initial public offering, net of issuance cost (shares)						10,294
Reclassification of redeemable convertible preferred stock warrant liability to equity	3,126,000						3,126,000
Stock option exercises	1,144,000						1,144,000
Stock option exercises (shares)					403
Stock-based compensation	15,171,000						15,171,000
Unrealized gain on available-for-salesecurities	(21,000)								(21,000)
Net loss	(89,449,000)									(89,449,000)
Ending Balance at Sep. 30, 2020	$ 354,333,000				$ 42,000		$ 816,306,000		$ 1,000	$ (462,016,000)
Ending Balance (shares) at Sep. 30, 2020					42,701

Condensed Statement of Redeem_2

Condensed Statement of Redeemable Convertible Preferred Stock and Stockholders' Equity (Deficit) (Parenthetical) $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)
Redeemable Convertible Preferred Stock
Issuance costs	$ 259

Condensed Statement of Cash Flo

Condensed Statement of Cash Flows - USD ($) $ in Thousands	9 Months Ended		12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019	Dec. 31, 2018
Cash flows from operating activities:
Net loss	$ (89,449)	$ (48,853)	$ (68,299)	$ (49,780)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	1,229	1,112	1,484	1,069
Non-cash lease expense	351	337
Amortization of right-of-use asset			451	425
Non-cash interest expense	497	691
Amortization of deferred financing costs and fees			893	1,348
Amortization (accretion) of premium (discount) on investments, net	60	(940)
Amortization of premium on investments			(983)	(779)
Provision for accounts receivable	29	267	59
Provision for inventories	443	199	326	442
Loss on disposal of property and equipment	5	293	293
Stock-based compensation	15,171	636	883	788
Change in fair value of redeemable convertible preferred stock warrant liability	93	(4,030)	(3,800)	262
Loss on extinguishment of term loan	1,567
Changes in operating assets and liabilities:
Accounts receivable	(3,197)	(3,298)	2,886	552
Inventories	(9,236)	(5,611)	(5,020)	(2,212)
Prepaid expenses and other assets	(5,397)	(101)	462	477
Other assets			234	207
Accounts payable	368	838	802	2,675
Accrued payroll and related benefits	3,894	991	3,119	647
Accrued expenses and other current liabilities	5,136	1,237	974	457
Accrued warranty liability	1,556	839	1,410	(443)
Deferred revenue	3,681	667	735	(55)
Accrued interest	(217)
Operating lease liabilities	241	(374)	(505)	(464)
Net cash used in operating activities	(73,175)	(55,100)	(70,292)	(46,442)
Cash flows from investing activities:
Purchases of property and equipment	(6,446)	(2,764)	(3,293)	(1,766)
Purchases of short-term investments	(32,884)	(88,103)	(91,878)	(132,310)
Sales and maturities of short-term investments	32,919	152,368	169,468	65,300
Net cash provided by (used in) investing activities	(6,411)	61,501	74,297	(68,776)
Cash flows from financing activities:
Proceeds from issuance of common stock upon initial public offering, net of issuance costs paid	255,728
Proceeds from cash exercise of redeemable convertible preferred stock warrants	4,288
Proceeds from issuance of redeemable convertible preferred stock, net of issuance costs	126,758			134,567
Proceeds from exercise of stock option	1,144	254	363	314
Proceeds from exercise of common stock warrant		76	76
Proceeds from issuance of term loan, net of issuance costs	29,630
Repayment of term loan and extinguishment costs	(30,985)
Repayment of finance lease	(8)	(6)	(9)	(9)
Payment of redeemable convertible preferred stock issuance costs		(181)	(181)
Net cash provided by financing activities	386,555	143	249	134,872
Net increase in cash, cash equivalents and restricted cash	306,969	6,544	4,254	19,654
Cash, cash equivalents and restricted cash as of beginning of period	37,669	33,415	33,415	13,761
Cash, cash equivalents and restricted cash as of end of period	344,638	39,959	37,669	33,415
Supplemental cash flow disclosures:
Cash paid for income taxes		35	35	9
Cash paid for interest	2,181	2,546	3,352	3,292
Cash paid for amounts included in the measurement of operating lease liabilities		374
Supplemental cash flow disclosures from investing and financing activities:
Reclassification of redeemable convertible preferred stock warrant liability for conversion of Series A redeemable preferred stock warrants into common stock warrants	1,252
Reclassification of redeemable convertible preferred stock warrant liability to additional paid-in capital	3,126
Conversion of redeemable convertible preferred stock into common stock upon initial public offering	456,561
Initial public offering issuance costs included in accrued expenses	923
Right-of-use assets obtained in exchange for lease liabilities	8,849
Transfer of inventories to property and equipment	1,579		3,119
Issuance of common stock on settlement of accrued dividend	41,763
Deemed dividend on settlement of accrued dividend	42,530
Capital expenditures included in accounts payable and accrued expenses	601	294	867	83
Gain on extinguishment of redeemable convertible preferred stock		117,598	117,597
Adjustment to redemption value on redeemable convertible preferred stock	$ 362	$ 134,760	$ 134,760	$ 23,300

Organization and Description of

Organization and Description of Business	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Description of Business	1. Description of Business Outset Medical, Inc. (the “Company”) was originally incorporated on May 5, 2003 in the state of Delaware under the name Home Dialysis Plus, Ltd. The name of the Company was changed to Outset Medical, Inc. on January 5, 2015. Outset Medical, Inc. is a medical technology company pioneering a first-of-its-kind The Company’s registration statement on Form S-1 Upon the Company’s IPO, the Company recognized $13.4 million of cumulative stock-based compensation associated with stock options that vest upon the achievement of market and performance conditions satisfied on the effectiveness of the IPO (see Note 10 for further discussion). Reverse Stock Split In September 2020, the Company’s board of directors and shareholders approved a certificate of amendment to the amended and restated certificate of incorporation to effect a reverse split of shares of the Company’s common stock on a 7.9-for-one Liquidity Since inception, the Company has incurred net losses and negative cash flows from operations. During the nine months ended September 30, 2020 and 2019, the Company incurred a net loss of $89.4 million and $48.9 million, respectively. As of September 30, 2020, the Company had an accumulated deficit of $462.0 million. As of September 30, 2020, the Company had cash, cash equivalents and short-term investments of $344.2 million, which are available to fund future operations, and restricted cash of $33.3 million, for a total cash, cash equivalents, restricted cash and short-term investments balance of $377.5 million. Management expects to continue to incur significant expenses for the foreseeable future and to incur operating losses in the near term while the Company makes investments to support its anticipated growth. Management believes that the Company’s existing cash, cash equivalents and short-term investments, which include the proceeds from the IPO, and cash generated from revenues from its products, as well as services and other sales, will be sufficient to meet its anticipated needs for at least the next 12 months from the issuance date of the accompanying condensed financial statements.	1. Organization and Description of Business Outset Medical, Inc. (the “Company”) was originally incorporated on May 5, 2003 in the state of Delaware under the name Home Dialysis Plus, Ltd. The name of the Company was changed to Outset Medical, Inc. on January 5, 2015. Outset Medical, Inc. is a medical technology company pioneering a first-of-its-kind Liquidity Since inception, the Company has incurred net losses and negative cash flows from operations. During the year ended December 31, 2019, the Company incurred a net loss of $68.3 million. As of December 31, 2019, the Company had an accumulated deficit of $372.6 million. As of December 31, 2019, the Company had cash and cash equivalents and short-term investments of $70.1 million, which are available to fund future operations, and restricted cash of $0.7 million, for a total cash and cash equivalents, restricted cash and short-term investments balance of $70.8 million. During the first quarter of 2020, the Company completed a Series E redeemable convertible preferred stock financing raising gross proceeds of $127.1 million (see Note 15 for further details). The Company has financed its operations primarily with the proceeds from the issuance of its redeemable convertible preferred stock and debt financing, and to a lesser extent, revenues from products, service and other sales. Management expects to continue to incur significant expenses for the foreseeable future and to incur operating losses in the near term while the Company makes investments to support its anticipated growth. The Company may raise additional capital through additional equity financing, debt financings or other sources. Management believes that the Company’s existing cash and cash equivalents, short-term investments, cash generated from revenues from its products as well as services and other sales, available borrowing capacity under the Perceptive Term Loan Agreement (see Note 8 for further details) and the proceeds from Series E financing in the first quarter of 2020 will be sufficient to meet its anticipated needs for the next 12 months from the date on which these financial statements are issued. The Company has evaluated and concluded there are no conditions or events, considered in the aggregate, that raise substantial doubt about its ability to continue as a going concern for a period of one year following the date these financial statements are issued.

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Basis of Presentation The accompanying condensed financial statements are unaudited and have been prepared in accordance with U.S. generally accepted accounting principles (U.S. GAAP) and on the same basis as the annual financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments, that are necessary for the fair statement of the Company’s financial position, results of operations, comprehensive loss and cash flows for the interim periods presented. The financial data and the other financial information disclosed in these notes to the condensed financial statements related to the nine-month periods are also unaudited. The results of operations for the nine months ended September 30, 2020 are not necessarily indicative of the results of operations to be anticipated for any other future annual or interim period. The condensed balance sheet as of December 31, 2019 included herein was derived from the audited financial statements as of that date. These unaudited condensed financial statements should be read in conjunction with the Company’s audited financial statements and related notes for the year ended December 31, 2019, which are included elsewhere in this prospectus. All share amounts disclosed in the notes to the condensed financial statements are rounded to the nearest thousand except for per share data. Use of Estimates The preparation of the accompanying condensed financial statements in conformity with U.S. GAAP requires management to make judgments, estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities as of the date of the accompanying condensed financial statements and the reported amounts of revenue and expenses. These judgments, estimates and assumptions are used for, but not limited to, revenue recognition, allowance for doubtful accounts, inventory valuation and write-downs, warranty obligations, the fair value of common stock and redeemable convertible preferred stock, the fair value of stock options, the fair value of the redeemable convertible preferred stock warrant liability, valuation of investments, recoverability of the Company’s net deferred tax assets and the related valuation allowance, and certain accrued expenses. The Company evaluates its estimates and assumptions on an ongoing basis using historical experience and other factors and adjusts those estimates and assumptions when facts and circumstances dictate. Actual results may differ from those estimates under different assumptions or conditions and the differences may be material. Cash, Cash Equivalents and Restricted Cash As of September 30, 2020, the restricted cash balance of $33.3 million primarily relates to contractual obligations under the SVB Loan and Security Agreement (see Note 7) and collateral for the building leases in San Jose, CA and Tijuana Mexico. The restricted cash balance of $0.7 million as of December 31, 2019 relates to collateral for the building leases. The following table provides a reconciliation of cash, cash equivalents and restricted cash that sum to the total of the amounts shown in the accompanying condensed statements of cash flows (in thousands): September 30, 2020 2019 Cash and cash equivalents $ 311,327 $ 39,216 Restricted cash 33,311 743 Total cash, cash equivalents and restricted cash $ 344,638 $ 39,959 Fair Value of Financial Instruments The Company determines the fair value of an asset or liability based on the assumptions that market participants would use in pricing the asset or liability in an orderly transaction between market participants at the measurement date. The identification of market participant assumptions provides a basis for determining what inputs are to be used for pricing each asset or liability. A fair value hierarchy has been established which gives precedence to fair value measurements calculated using observable inputs over those using unobservable inputs. This hierarchy prioritizes the inputs into three broad levels as follows: Level 1: Quoted prices in active markets for identical instruments; Level 2: Other significant observable inputs (including quoted prices in active markets for similar instruments); and Level 3: Significant unobservable inputs (including assumptions in determining the fair value of certain investments). The Company’s cash and cash equivalents, restricted cash, short-term investments, accounts receivable, accounts payable and accrued liabilities approximate their fair value due to their short maturities. Management believes that its term loan bears interest at the prevailing market rates for instruments with similar characteristics; accordingly, the carrying value of this instrument approximates its fair value. Money market funds are highly liquid investments and are actively traded. The pricing information on the Company’s money market funds are readily available and can be independently validated as of the measurement date. This approach results in the classification of these securities as Level 1 of the fair value hierarchy. The Company has issued redeemable convertible preferred stock warrants and estimated the fair value of these warrants using the Black-Scholes option pricing model, which is considered to be a Level 3 fair value measurement. The assumptions that were based on the individual characteristics of the warrants on the valuation date, as well as assumptions for future financings, expected volatility, expected life, yield, and risk-free interest rate. Effective on the date of the IPO, the redeemable convertible preferred stock warrants were considered to be indexed to the Company’s stock, and accordingly, the fair value of redeemable convertible preferred stock warrant liability was remeasured immediately prior to the IPO (See Note 4). Accrued Warranty Liability The Company generally provides a one-year Contract Liabilities—Deferred Revenue The timing of revenue recognition may differ from the timing of invoicing to customers. The Company records deferred revenue when revenue is recognized subsequent to invoicing. For multi-year service agreements, the Company generally invoices customers annually at the beginning of each annual coverage period. Deferred revenue that will be recognized during the 12 months following the balance sheet date is recorded as the current portion of deferred revenue and the remaining portion is recorded as noncurrent. Redeemable Convertible Preferred Stock Warrant Liability The Company has accounted for its freestanding warrants to purchase shares of the Company’s redeemable convertible preferred stock as liabilities at fair value upon issuance primarily because the shares underlying the warrants contained contingent redemption features outside the control of the Company. The warrants were subject to re-measurement at additional paid-in capital, Revenue The Company’s revenue is generated primarily from the sale of its products and services. Product revenue consists primarily of sales of the Tablo console and related consumables, including Tablo cartridges, used in treatment delivery. Service and other revenue consists primarily of revenue generated from consoles service contracts and other revenue from shipping and handling charged to customers. The Company considers each product and each service contract to be a distinct performance obligation. Revenue is recognized when a performance obligation is satisfied, which occurs when control of the promised products or services is transferred to the customer in an amount that reflects the consideration the Company expects to receive in exchange for those products or services. Revenue from product sales is recognized at a point in time when management has determined that control has transferred to the customer, which is generally when legal title has transferred to the customer. Revenue from service contracts is recognized as the output of the service is transferred to the customer over time, typically evenly over the contract term. Revenue is recognized net of allowances for returns and any taxes collected from customers, which are subsequently remitted to governmental authorities. The Company’s contracts with customers often include promises to transfer multiple products and services to a customer. Determining whether products and services are considered distinct performance obligations that should be accounted for separately versus together may require significant judgment. Judgment is also required to determine the stand-alone selling price (SSP) for each distinct performance obligation. The Company uses an observable price to estimate SSP for items that are sold separately, including customer support agreements. In instances where SSP is not directly observable, such as when the Company does not sell the product or service separately, the Company determines the SSP using information that may include market conditions and other observable inputs. When stand-alone selling prices have not been established for products, the Company will utilize the residual method to allocate revenue. The Company may offer additional goods or services to customers at the inception of customer contracts at prices not at SSP. This is considered a material right and an additional performance obligation of the contract. SSP is assigned based on the estimated value of the material right. Costs associated with product sales include commissions. The Company applies the practical expedient to expense the commissions as incurred as the expected amortization period is one year or less. Commissions are recorded as sales and marketing expenses in the accompanying condensed statements of operations. Operating Lease Arrangements The Company enters into operating lease arrangements that contain both lease and non-lease non-lease non-lease Shipping and Handling Costs Shipping and handling charged to customers are recorded as revenue. Shipping and handling costs are expensed as incurred and are included in sales and marketing expenses. Stock-Based Compensation The Company’s stock-based compensation relates to stock options with a service condition, stock options with performance and market-based vesting conditions, and stock purchase rights under the Company’s Employee Stock Purchase Plan (ESPP). Stock-based compensation for its stock-based awards is based on their grant date fair value. Service-based options initially granted to an optionee generally vest at a rate of 25% on the first anniversary of the original vesting date, with the balance vesting monthly over the remaining three years. Any subsequent follow-on For stock options with performance and market-based vesting conditions, stock-based compensation is recognized when the performance vesting condition is considered probable of being satisfied. Prior to the Company’s IPO in September 2020, the Company had not recognized any stock-based compensation as the satisfaction of the performance condition was not considered probable. Upon the closing of the IPO, the Company recorded a cumulative stock-based compensation using the accelerated attribution method as the performance condition was satisfied. Compensation related to these options is not reversed if the achievement of the market condition does not occur. The fair value of these stock options is estimated using the Monte Carlo approach. Net Loss Per Share Attributable to Common Stockholders Basic net loss per share attributable to common stockholders is calculated by dividing the net loss attributable to common stockholders by the weighted-average number of shares of common stock outstanding for the period, without consideration for potential dilutive securities. Diluted net loss per share is computed by dividing the net loss attributable to common stockholders by the weighted-average number of common shares and common share equivalents of potentially dilutive securities outstanding for the period. For purposes of the diluted net loss per share calculation, redeemable convertible preferred stock, warrants and awards under the Company’s equity compensation plan are considered to be potentially dilutive securities. For periods in which the Company reports net losses, diluted net loss per share attributable to common stockholders is the same as basic net loss per share attributable to common stockholders because potentially dilutive shares of common stock are not assumed to have been issued if their effect is antidilutive. Therefore, basic and diluted net loss per share was the same for all periods presented. Recently Adopted Accounting Pronouncements In August 2018, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2018-13, Fair Value Measurement (Topic 820): Disclosure Framework—Changes to the Disclosure Requirements for Fair Value Measurement 2018-13). 2018-13 Recently Issued Accounting Pronouncements Not Yet Adopted In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments—Credit Losses (Topic 326) Measurement of Credit Losses on Financial Instruments 2016-13), available-for-sale available-for-sale 2016-13 2019-10, Financial Instruments—Credit Losses (Topic 326), Derivatives and Hedging (Topic 815) and Leases (Topic 842): Effective Dates ASU 2016-13 2016-13 2016-13	2. Summary of Significant Accounting Policies Basis of Presentation The Company’s financial statements have been prepared in accordance with United States generally accepted accounting principles (“U.S. GAAP”). Use of Estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make judgements, estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities as of the date of the financial statements and the reported amounts of revenue and expenses. These judgements, estimates and assumptions are used for, but not limited to, revenue recognition, allowance for doubtful accounts, inventory valuation and write-downs, warranty obligations, fair value of common stock and redeemable convertible preferred stock, the fair value of stock options, the fair value of redeemable convertible preferred stock warranty liability, valuation of investments, recoverability of the Company’s net deferred tax assets and the related valuation allowance, and certain accrued expenses. The Company evaluates its estimates and assumptions on an ongoing basis using historical experience and other factors and adjusts those estimates and assumptions when facts and circumstances dictate. Actual results may differ from those estimates under different assumptions or conditions and the differences may be material. Segment The Company operates as a single operating segment. The Company’s chief operating decision maker, its Chief Executive Officer, reviews financial information on an aggregate basis for the purposes of allocating resources and evaluating financial performance. The Company has only operated in the United States since its inception and has derived its revenue from sales to customers in the United States. Cash, Cash Equivalents and Restricted Cash The Company considers all highly liquid investments purchased with an original maturity of three months or less at the date of purchase to be cash equivalents. As of December 31, 2018 and 2019, the Company’s cash equivalents were held in institutions in the United States and include deposits in a money market fund which were unrestricted as to withdrawal or use. As of December 31, 2018 and 2019, the Company had restricted cash of $0.2 million and $0.7 million, respectively, representing collateral for the Company’s building leases in San Jose, CA. Restricted cash is classified in other assets in the accompanying balance sheets. The following table provides a reconciliation of cash, cash equivalents and restricted cash reported within the balance sheets that sum to the total of the amounts shown in the statements of cash flows: December 31, 2018 2019 Cash and cash equivalents $ 33,264 $ 36,926 Restricted cash 151 743 $ 33,415 $ 37,669 Investments The Company classifies its investment securities as available-for-sale. A decline in the fair value of any security below cost that is deemed other than temporary results in a charge to earnings and the corresponding establishment of a new cost basis for the security. Premiums (discounts) are amortized (accreted) over the life of the related security as an adjustment to yield using the straight-line interest method. Dividend and interest income are recognized when earned. Realized gains and losses are included in earnings and are derived using the specific identification method for determining the cost of securities sold. Fair Value of Financial Instruments The Company determines the fair value of an asset or liability based on the assumptions that market participants would use in pricing the asset or liability in an orderly transaction between market participants at the measurement date. The identification of market participant assumptions provides a basis for determining what inputs are to be used for pricing each asset or liability. A fair value hierarchy has been established which gives precedence to fair value measurements calculated using observable inputs over those using unobservable inputs. This hierarchy prioritized the inputs into three broad levels as follows: Level 1: Quoted prices in active markets for identical instruments; Level 2: Other significant observable inputs (including quoted prices in active markets for similar instruments); and Level 3: Significant unobservable inputs (including assumptions in determining the fair value of certain investments). The Company’s cash and cash equivalents, restricted cash, accounts receivable, accounts payable and accrued liabilities approximate their fair value due to their short maturities. Management believes that its term loan bears interest at the prevailing market rates for instruments with similar characteristics; accordingly, the carrying value of this instrument approximates its fair value. Money market funds are highly liquid investments and are actively traded. The pricing information on the Company’s money market funds are readily available and can be independently validated as of the measurement date. This approach results in the classification of these securities as Level 1 of the fair value hierarchy. There were no transfers between Levels 1, 2 or 3 for any of the periods presented. The Company has issued redeemable convertible preferred stock warrants for which fair value is determined using Level 3 inputs (see Note 4). Concentration of Credit Risk Financial instruments that potentially subject the Company to a concentration of credit risk consist of cash and cash equivalents, restricted cash, short-term investments and accounts receivable. Substantially all the Company’s cash and cash equivalents, restricted cash and investments are held at one financial institution in the United States that management believes is of high credit quality. Such deposits may, at times, exceed federally insured limits or may not be covered by deposit insurance at all. The Company has not experienced any credit losses on its cash and cash equivalents, restricted cash or short-term investments through December 31, 2019. Four customers accounted for 20%, 18%, 14% and 12% of revenues, respectively, in the year ended December 31, 2018. One customer accounted for 11% of revenues in the year ended December 31, 2019. Accounts receivable are unsecured and the Company does not require collateral; however, the Company does assess the collectability of accounts receivable based on a number of factors, including past transaction history with, and the creditworthiness of, the customer. Accordingly, the Company is exposed to credit risk associated with accounts receivable. Four customers accounted for 28%, 24%, 16% and 12% of accounts receivable, respectively, as of December 31, 2018. Four customers accounted for 22%, 13%, 11% and 10% of accounts receivable, respectively, as of December 31, 2019. To reduce risk, the Company closely monitors the amounts due from its customers and assesses the financial strength of its customers through a variety of methods that include, but are not limited to, engaging directly with customer operations and leadership personnel, visiting customer locations to observe operating activities, and assessing customer longevity and reputation in the marketplace. As a result, the Company believes that its accounts receivable credit risk exposure is limited. The Company provides for uncollectible amounts when specific credit problems are identified. As of December 31, 2018, the Company did not have an allowance for doubtful accounts. As of December 31, 2019, the Company recorded an allowance for doubtful accounts of $59,000. Inventories Inventories are stated at the lower of cost or net realizable value. Cost is determined using the standard cost method, which approximates actual costs as determined on a first-in, first-out Property and Equipment, Net Property and equipment, net is stated at cost, net of accumulated depreciation. Depreciation is computed using the straight-line method based on the estimated useful lives of the assets, which is generally two to five years. Leasehold improvements are amortized using the straight-line method over the shorter of the assets estimated useful lives or the remaining term of the lease. Maintenance and repairs are charged to expense as incurred. Significant improvements that substantially enhance the useful life of an asset are capitalized and depreciated. When assets are retired or disposed of, the cost together with related accumulated depreciation is removed from the balance sheet and any resulting gain or loss is reflected in the Company’s statements of operations in the period realized. Leases The Company accounts for its lease arrangements in accordance with FASB Accounting Standards Codification (“ASC”) Topic 842, Leases right-of-use ROU assets represent the Company’s right to use an underlying asset for the lease term and lease liabilities represent the Company’s obligation to make lease payments arising from the lease. Operating lease ROU assets and liabilities are recognized based on the present value of lease payments over the lease term at commencement date of the lease. ROU assets also include any initial direct costs incurred and any lease payments made at or before the lease commencement date, less any lease incentive received. As most of the Company’s leases do not provide an implicit interest rate, the Company uses its incremental borrowing rate based on the information available at the commencement date in determining the present value of lease payments. The Company uses the implicit rate when readily determinable. The Company’s lease terms may include options to extend or terminate the lease when it is reasonably certain that the Company will exercise that option. Lease expense for lease payments is recognized on a straight-line basis over the lease term. The Company does not recognize a ROU asset nor lease liability for short-term leases. Instead, it recognizes these short-term lease payments in the income statement on a straight-line basis over the lease term. Short-term leases are defined as 12 months or less in duration. Impairment for Long-Lived Assets Long-lived assets, such as property and equipment are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. If circumstances require a long-lived asset or asset group to be tested for possible impairment, the Company first compares undiscounted cash flows expected to be generated by that asset or asset group to its carrying value. If the carrying value of the long-lived asset or asset group is not recoverable on an undiscounted cash flow basis, an impairment is recognized to the extent that the carrying value exceeds its fair value. Fair value is determined through various valuation techniques including discounted cash flow models, quoted market values and third-party independent appraisals, as considered necessary. There were no such impairment losses as of December 31, 2018 and 2019. Deferred Loan Commitment Costs Costs incurred to obtain term loan commitments (see Note 8) are recorded in other assets and amortized to interest expense over the term of the commitment on a straight-line basis. When amounts are borrowed under a loan commitment in the future, a proportionate amount of the remaining unamortized deferred cost will be reclassified as a debt discount and amortized over the remaining term of the term loan using the effective interest method. If a commitment for a term loan expires unused, the related balance is charged to interest expense. As of December 31, 2018, the total unamortized deferred loan commitment costs recorded in other assets amounted to $0.1 million. As of December 31, 2019, there was no unamortized deferred loan commitment balance. Accrued Warranty Liability The Company generally provides a one-year Deferred Revenue Deferred revenue consists of payments received in advance of revenue recognition primarily related to console service agreements. Revenue under these agreements is recognized over the related service period. Deferred revenue that will be recognized during the 12 months following the balance sheet date is recorded as deferred revenue, current and the remaining portion is recorded as deferred revenue, noncurrent on the accompanying balance sheets. Redeemable Convertible Preferred Stock Warrant Liability The Company has accounted for its freestanding warrants to purchase shares of the Company’s redeemable convertible preferred stock as liabilities at fair value upon issuance primarily because the shares underlying the warrants contain contingent redemption features outside the control of the Company. The warrants are subject to re-measurement at The carrying value of the warrants will continue to be adjusted until such time as these instruments are exercised, expire or convert into warrants to purchase shares of the Company’s common stock. At that time, the liabilities will be reclassified to additional paid-in capital, The Company estimated the fair value of these liabilities using the Black-Scholes option pricing model and assumptions that were based on the individual characteristics of the warrants on the valuation date, as well as assumptions for future financings, expected volatility, expected life, yield, and risk-free interest rate. Defined Contribution Plan The Company has a defined contribution retirement savings plan under Section 401(k) of the Internal Revenue Code. This plan allows eligible employees to defer a portion of their annual compensation on a pre-tax Revenue The Company recognizes revenue in accordance with ASC Topic 606, Revenue from Contracts with Customers (1) Identify the contract(s) with a customer; (2) Identify the performance obligations in the contract; (3) Determine the transaction price; (4) Allocate the transaction price to the performance obligations in the contract; and (5) Recognize revenue when (or as) the entity satisfies a performance obligation. The Company’s revenue is generated primarily from the sale of its products and services. Product revenue consists primarily of sales of the Tablo console and related consumables, including the Tablo cartridge, used in treatment delivery. Service revenue consists primarily of revenue generated from consoles service contracts. The Company considers each product and each service contract to be a distinct performance obligation. Revenue is recognized when a performance obligation is satisfied, which occurs when control of the promised products or services is transferred to the customer in an amount that reflects the consideration the Company expects to receive in exchange for those products or services. Revenue from product sales is recognized at a point in time when management has determined that control has transferred to the customer, which is generally when legal title has transferred to the customer. Revenue from service contracts is recognized as the output of the service is transferred to the customer over time, typically evenly over the contract term. Revenue is recognized net of allowances for returns and any taxes collected from customers, which are subsequently remitted to governmental authorities. The Company’s contracts with customers often include promises to transfer multiple products and services to a customer. Determining whether products and services are considered distinct performance obligations that should be accounted for separately versus together may require significant judgment. Judgment is also required to determine the stand-alone selling price (“SSP”) for each distinct performance obligation. The Company uses an observable price to estimate SSP for items that are sold separately, including customer support agreements. In instances where SSP is not directly observable, such as when the Company does not sell the product or service separately, the Company determines the SSP using information that may include market conditions and other observable inputs. When stand-alone selling prices have not been established for products, the Company will utilize the residual method to allocate revenue. The Company may offer additional goods or services to customers at the inception of customer contracts at prices not at SSP. This is considered a material right and an additional performance obligation of the contract. SSP is assigned based on the estimated value of the material right. Costs associated with product sales include commissions. The Company applies the practical expedient to expense the commissions as incurred as the expected amortization period is one year or less. Commissions are recorded as sales and marketing expenses in the statements of operations. Operating Lease Arrangements From time to time, the Company enters into operating lease arrangements that contain both lease and non-lease non-lease non-lease Shipping and Handling Costs Shipping and handling charged to customers are recorded as revenue. Shipping and handling costs, including the associated personnel, are expensed as incurred and are included in sales and marketing expenses. Contract Balances The timing of revenue recognition may differ from the timing of invoicing to customers. The Company records an unbilled receivable when revenue is recognized prior to invoicing, or deferred revenue when revenue is recognized subsequent to invoicing. For multi-year service agreements, the Company generally invoices customers annually at the beginning of each annual coverage period. Research and Development The Company expenses all research and development costs as incurred. These expenses include the costs of proprietary research and development efforts, quality engineering, clinical studies and trials and regulatory affairs. Costs include salaries, employee benefits, and other headcount-related costs, prototype development costs, contract and other outside service fees, depreciation expense and allocated costs including facilities and information technology. Advertising Costs Advertising costs are expensed as incurred. For the years ended December 31, 2018 and 2019, advertising costs were not significant. Stock-Based Compensation The Company accounts for stock-based compensation arrangements with employees and non-employee non-employees non-employee Service-based options initially granted to an optionee generally vest at a rate of 25% on the first anniversary of the original grant date, with the balance vesting monthly over the remaining three years. Any subsequent follow-on For stock options with performance and market-based vesting conditions, stock-based compensation is recognized when a performance vesting condition is considered probable of being achieved. Once the performance vesting condition is considered probable of being achieved, compensation costs related to awards with a performance and market-based condition are recognized regardless of whether the market condition is ultimately satisfied using the accelerated attribution method. Compensation cost is not reversed if the achievement of the market condition does not occur. The fair value of these share-based payment awards is estimated using the Monte Carlo approach. Income Taxes The Company accounts for income taxes under the asset and liability method. Under this method, deferred tax assets and liabilities are determined based on differences between financial reporting and tax reporting bases of assets and liabilities and remeasured using enacted tax rates and laws that are expected to be in effect when the differences are expected to reverse. Realization of deferred tax assets is dependent upon future earnings, the timing and amount of which are uncertain. The Company utilizes a two-step The Company includes any penalties and interest expense related to income taxes as a component of other expense, net, as necessary. Net Loss per Share Attributable to Common Stockholders Basic net loss per share attributable to common stockholders is calculated by dividing the net loss attributable to common stockholders by the weighted-average number of shares of common stock outstanding for the period, without consideration for potential dilutive securities. Diluted net loss per share is computed by dividing the net loss by the weighted-average number of common shares and common share equivalents of potentially dilutive securities outstanding for the period. For purposes of the diluted net loss per share calculation, redeemable convertible preferred stock, warrants and common stock options are considered to be potentially dilutive securities. As the Company was in a loss position for the years ended December 31, 2018 and 2019, basic net loss per share attributable to common stockholders is the same as diluted net loss per share attributable to common stockholders because the effects of potentially dilutive securities are antidilutive. Recently Adopted Accounting Pronouncements In June 2018, the FASB issued ASU No. 2018-07, Compensation—Stock Compensation (Topic 718) Improvements to Nonemployee Share-Based Payment Accounting No. 2018-07). No. 2018-07 In November 2016, the FASB issued ASU No. 2016-18, Statement of Cash Flows, Restricted Cash (Topic 230) Recently Issued Accounting Pronouncements Not Yet Adopted In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments—Credit Losses (Topic 326) Measurement of Credit Losses on Financial Instruments No. 2016-13), available-for-sale available-for-sale 2016-13 No. 2019-10, Financial Instruments—Credit Losses (Topic 326), Derivatives and Hedging (Topic 815) and Leases (Topic 842): Effective Dates No. 2016-13 No. 2016-13 In August 2018, the FASB issued ASU No. 2018-13, Fair Value Measurement (Topic 820): Disclosure Framework—Changes to the Disclosure Requirements for Fair Value Measurement No. 2018-13), Fair Value Measurement 2018-13

Revenue and Deferred Revenue

Revenue and Deferred Revenue	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Revenue from Contract with Customer [Abstract]
Revenue and Deferred Revenue	3. Revenue and Deferred Revenue Disaggregation of Revenue Revenue by source consisted of the following (in thousands): Nine Months Ended 2020 2019 Consoles $ 22,230 $ 6,248 Consumables 4,205 1,253 Total product revenue 26,435 7,501 Service and other revenue 6,253 492 Total revenue $ 32,688 $ 7,993 Performance Obligations As of September 30, 2020, the aggregate amount of the transaction price allocated to the remaining performance obligations related to customer service contracts that are unsatisfied or partially unsatisfied was $4.7 million, which is recorded as deferred revenue on the Company’s condensed balance sheets. Of that amount, $4.1 million will be recognized as revenue during the next 12 months and approximately $0.6 million thereafter. Contract Liabilities The contract liabilities consist of deferred revenue which represents payments received in advance of revenue recognition related to console service agreements and for prepayments for products or services yet to be delivered. Revenue under these agreements is recognized over the related service period. The following table summarized the Company’s contract liabilities (in thousands): September 30, December 31, Deferred revenue, current $ 4,132 $ 883 Deferred revenue, noncurrent 566 134 Total Deferred revenue $ 4,698 $ 1,017 Revenue recorded during the nine months ended September 30, 2020 included $0.8 million of previously deferred revenue that was included in contract liabilities as of December 31, 2019.	3. Revenue from Contracts with Customers The Company’s revenue is generated primarily from the sale of its products and services solely from U.S. based customers. Product revenue primarily consists of sales of consoles and consumables. Service revenue primarily consists of revenue generated from consoles service contracts. Additionally, the Company has an operating lease arrangement which contains both lease and non-lease Disaggregation of Revenue Revenue by source consisted of the following (in thousands): December 31, 2018 2019 Consoles $ 1,226 $ 12,187 Consumables 523 1,563 Total product revenue $ 1,749 $ 13,750 Service revenue 258 1,328 Total revenue $ 2,007 $ 15,078 Performance Obligations As of December 31, 2019, the aggregate amount of the transaction price allocated to the remaining performance obligations related to customer service contracts that are unsatisfied or partially unsatisfied was $1.0 million, which is recorded as deferred revenue on the Company’s balance sheet. Of that amount, $0.9 million will be recognized as revenue during the year ended December 31, 2020 and approximately $0.1 million thereafter. Contract Balances The Company invoices its customers based on the billing schedules in its sales arrangements. Payments are generally due 30 days from date of invoice. Contract liabilities consist mainly of deferred revenue. Contract liabilities primarily relate to consideration received from customers prior to transferring goods or services to the customer. The following information summarizes the Company’s contract liabilities (in thousands): December 31, 2018 2019 Deferred revenue, current $ 269 $ 883 Deferred revenue, noncurrent $ 13 $ 134 During the year ended December 31, 2018, the Company recognized $0.3 million of revenue that was included in deferred revenue balance as of December 31, 2017. During the year ended December 31, 2019, the Company recognized $0.3 million of revenue that was included in the deferred revenue balance as of December 31, 2018.

Fair Value Measurements

Fair Value Measurements	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Fair Value Measurements	4. Fair Value Measurements The following tables summarize the Company’s financial assets and liabilities measured at fair value on a recurring basis by level within the fair value hierarchy (in thousands): September 30, 2020 Valuation Hierarchy Amortized Costs Gross Unrealized Holding Gains Gross Unrealized Holding Losses Aggregate Fair Value Assets: Cash equivalents: Money market funds Level 1 $ 43,058 $ — $ — $ 43,058 Short-term investments: U.S. Treasury securities Level 1 24,992 1 — 24,993 Corporate debt Level 2 7,895 — — 7,895 Total assets $ 75,945 $ 1 $ — $ 75,946 December 31, 2019 Valuation Hierarchy Amortized Costs Gross Unrealized Holding Gains Gross Unrealized Holding Losses Aggregate Fair Value Assets: Cash equivalents: Money market funds Level 1 $ 29,761 $ — $ — $ 29,761 Commercial paper Level 2 2,299 — — 2,299 Short-term investments: Commercial paper Level 2 10,972 — — 10,972 Corporate debt Level 2 17,357 19 — 17,376 Asset-backed securities Level 2 4,801 3 — 4,804 Total assets $ 65,190 $ 22 $ — $ 65,212 Liabilities: Redeemable convertible preferred stock warrant liability Level 3 $ 4,285 $ — $ — $ 4,285 Total liabilities $ 4,285 $ — $ — $ 4,285 As of September 30, 2020, the remaining contractual maturities for available-for-sale Impairment assessments are made at the individual security level each reporting period. When the fair value of an available-for-sale available-for-sale Redeemable Convertible Preferred Stock Warrant Liability The valuation of the Company’s redeemable convertible preferred stock warrant liability contained unobservable inputs that reflected the Company’s own assumptions for which there was little, if any, market activity for at the measurement date. Accordingly, the Company’s redeemable convertible preferred stock warrant liability was measured at fair value on a recurring basis using unobservable inputs and were classified as Level 3 inputs, and any change in fair value of the redeemable convertible preferred stock warrant liability was recognized in the accompanying condensed statements of operations. Effective on the date of the IPO, the redeemable convertible preferred stock warrants were considered to be indexed to the Company’s stock and now meet the criteria to be classified in equity. The Company remeasured the warrants immediately prior to the IPO. The fair value of the Series A redeemable convertible preferred stock warrants which were converted into common stock warrants was determined using the Black-Scholes option-pricing model and deemed a Level 3 fair value measurement. The fair value of Series B and C redeemable convertible preferred stock warrants which were exercised was determined using the intrinsic method based on the IPO price of $27.00 per share and deemed a Level 2 fair value measurement. Subsequently, the entire redeemable convertible preferred stock warrants liability was reclassified to additional paid-in The change in fair value of the redeemable convertible preferred stock warrant liability was as follows (in thousands): Balance at December 31, 2019 $ 4,285 Change in fair value 93 Conversion of Series A redeemable convertible preferred stock warrants to common stock warrants upon the closing of the IPO (1,252 ) Reclassified to additional paid-in (3,126 ) Balance at September 30, 2020 $ —	4. Fair Value Measurements The following tables present the Company’s assets and liabilities that are measured at fair value on a recurring basis by level within the fair value hierarchy (in thousands): December 31, 2018 Valuation Amortized Gross Gross Aggregate Assets: Cash equivalents: Money market funds Level 1 $ 21,889 $ — $ — $ 21,889 Repurchase agreements Level 2 6,000 — — 6,000 Short-term investments: Government debt Level 1 13,981 — (1 ) 13,980 Commercial paper Level 2 44,263 — — 44,263 Corporate debt Level 2 30,852 — (36 ) 30,816 Asset-backed securities Level 2 20,482 — (23 ) 20,459 Total assets $ 137,467 $ $ (60 ) $ 137,407 Liabilities: Redeemable convertible preferred stock warrant liability Level 3 $ 8,085 $ — $ — $ 8,085 Total liabilities $ 8,085 $ — $ — $ 8,085 December 31, 2019 Valuation Amortized Gross Gross Aggregate Assets: Cash equivalents: Money market funds Level 1 $ 29,761 $ — $ — $ 29,761 Commercial paper Level 2 2,299 — — 2,299 Short-term investments: Commercial paper Level 2 10,972 — — 10,972 Corporate debt Level 2 17,357 19 — 17,376 Asset-backed securities Level 2 4,801 3 — 4,804 Total assets $ 65,190 $ 22 $ — $ 65,212 Liabilities: Redeemable convertible preferred stock warrant liability Level 3 $ 4,285 $ — $ — $ 4,285 Total liabilities $ 4,285 $ — $ — $ 4,285 There were no transfers between levels during the years ended December 31, 2018 and 2019. The Company’s Level 2 securities are valued using third-party pricing sources. The pricing services utilize industry standard valuation models, including both income and market-based approaches, for which all significant inputs are observable, either directly or indirectly, to estimate fair value. These inputs include reported trades of and broker/dealer quotes on the same or similar securities, issuer credit spreads, benchmark securities, prepayment/default projections based on historical data and other observable inputs. The Company validates the prices provided by its third-party pricing services by understanding the models used, obtaining market values from other pricing sources and confirming those securities traded in active markets. As of December 31, 2019, the remaining contractual maturities for available-for-sale For the years ended December 31, 2018 and 2019, interest income was $1.8 million and $2.5 million, respectively. Impairment assessments are made at the individual security level each reporting period. When the fair value of an available-for-sale As of December 31, 2018, some of the Company’s available-for-sale available-for-sale The change in fair value of the Company’s redeemable convertible preferred stock warrant liability was as follows (in thousands): Years Ended December 31, 2018 2019 Beginning balance $ 7,823 $ 8,085 Change in fair value of redeemable convertible preferred stock warrant liability 262 (3,800 ) Ending balance $ 8,085 $ 4,285 The valuation of the Company’s redeemable convertible preferred stock warrant liability contains unobservable inputs that reflect the Company’s own assumptions for which there is little, if any, market activity for at the measurement date. Accordingly, the Company’s redeemable convertible preferred stock warrant liability is measured at fair value on a recurring basis using unobservable inputs and are classified as Level 3 inputs, and any change in fair value of the redeemable convertible preferred stock warrant liability is recognized in the statements of operations. Refer to Note 9 for the valuation technique and assumptions used in estimating the fair value of the redeemable convertible preferred stock warrant liability.

Balance Sheet Components

Balance Sheet Components	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Balance Sheet Components	5. Balance Sheet Components Inventories Inventories consist of the following (in thousands): September 30, December 31, Raw materials $ 6,163 $ 1,143 Work in process 2,758 842 Finished goods 2,889 2,611 Total inventories $ 11,810 $ 4,596 Other Assets Other assets consist of the following (in thousands): September 30, December 31, Prepaid insurance, noncurrent $ 1,878 $ — Deposits 99 82 Total other assets $ 1,977 $ 82 Accrued Expenses and Other Current Liabilities Accrued expenses and other current liabilities consist of the following (in thousands): September 30, December 31, Accrued inventory $ 4,560 $ 798 Accrued research and development expenses 212 421 Accrued professional services 2,784 553 Others 1,403 1,137 Total accrued expenses and other current liabilities $ 8,959 $ 2,909 Accrued Warranty Liability The change in accrued warranty liability is presented in the following table (in thousands): September 30, December 31, Balance at the beginning of the period $ 1,702 $ 293 Additions charge to cost of product revenue 3,808 2,578 Consumption (2,252 ) (1,169 ) Balance at the end of the period $ 3,258 $ 1,702	5. Balance Sheet Components Inventories Inventories consist of the following (in thousands): December 31, 2018 2019 Raw material $ 846 $ 1,143 Work-in-process 1,728 842 Finished goods 448 2,611 $ 3,022 $ 4,596 Property and Equipment, net Property and equipment, net consist of the following (in thousands): December 31, 2018 2019 Computers and software $ 1,137 $ 1,857 Dialysis equipment 1,038 3,904 Machinery and equipment 991 761 Production tooling 871 2,782 Furniture and fixtures 487 1,087 Leasehold improvements 174 174 Total property and equipment 4,698 10,565 Less: Accumulated depreciation and amortization (2,223 ) (2,670 ) Property and equipment, net $ 2,475 $ 7,895 Total depreciation and amortization expense for the years ended December 31, 2018 and 2019 was $1.1 million and $1.5 million, respectively. Accrued Expenses and Other Current Liabilities Accrued expenses and other current liabilities consist of the following (in thousands): December 31, 2018 2019 Accrued inventory $ 299 $ 798 Accrued research and development expenses 236 421 Accrued professional services 179 553 Operating lease liabilities 505 — Other 1,222 1,137 $ 2,441 $ 2,909 Accrued Warranty Liability The change in accrued warranty liability is presented in the following table (in thousands): Years Ended December 31, 2018 2019 Balance at beginning of the year $ 736 $ 293 Provision for warranty liability made during the year 341 2,578 Consumption during the year (784 ) (1,169 ) Balance at end of the year $ 293 $ 1,702

Leases

Leases	12 Months Ended
	Dec. 31, 2019
Leases [Abstract]
Leases	6. Leases The Company has an operating lease agreement for its facility and office space that commenced in October 2014, the initial terms of which expired in December 2019, and which is currently leased on a month-to-month month-to-month The following table presents the Company’s ROU assets and lease liabilities (in thousands): December 31, Lease Classification Classification 2018 2019 Assets: Operating Current assets $ 451 $ — Financing Property and equipment 19 6 Total ROU assets $ 470 $ 6 Liabilities: Current: Operating Accrued expenses and other current liabilities $ 505 $ — Financing Accrued expenses and other current liabilities 10 9 Noncurrent: Operating Operating lease liability — — Financing Long-term debt 9 — Total lease liabilities $ 524 $ 9 As of December 31, 2019, the minimum lease payments of the Company’s lease liabilities are as follows (in thousands): Finance Year Ending December 31: 2020 $ 9 Total lease payments $ 9 Less: imputed interest — Total lease liabilities $ 9 In September 2019, the Company entered into an operating lease agreement for its new facility and office space that will commence in April 2020 and expires in March 2027. This operating lease contains a free rent period and an escalation clause. The landlord provided the Company with a tenant improvement allowance of up to $2.0 million. The Company issued an irrevocable standby letter of credit in the amount of $0.6 million in lieu of a cash security deposit. The letter of credit is fully secured by cash held at the bank in a restricted account. The total future minimum lease payments associated with this operating lease agreement are approximately $8.8 million. Operating lease cost for the years ended December 31, 2018 and 2019 were $0.6 million each, respectively. Principal payments related to the Company’s finance lease for the year ended December 31, 2018 and 2019 were $8,000 and $9,000, respectively. As of December 31, 2019, the weighted-average remaining lease term was 0.5 years and the weighted-average discount rate was 10.6% for the Company’s financing lease. The following information represents supplemental disclosure for the statements of cash flows related to the Company’s lease (in thousands): Years Ended December 31, 2018 2019 Supplemental Cash Flows Information: Cash paid for amounts included in the measurement of lease liabilities: Cash used in operating activities: Operating leases $ 464 $ 505 Financing leases $ 1 $ 1 Cash used in financing activities: Financing leases $ 9 $ 9

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	6. Commitments and Contingencies Litigation From time to time, the Company may be involved in lawsuits, claims, investigations and proceedings, consisting of intellectual property, commercial, employment and other matters, which arise in the ordinary course of business. The Company is not currently aware of any matters that would be material to the financial statements as a whole. Indemnifications In the ordinary course of business, the Company often includes standard indemnification provisions in its arrangements with its partners, suppliers and vendors. Pursuant to these provisions, the Company may be obligated to indemnify such parties for losses or claims suffered or incurred in connection with its service, breach of representations or covenants, intellectual property infringement or other claims made against such parties. These provisions may limit the time within which an indemnification claim can be made. It is not possible to determine the maximum potential amount under these indemnification obligations due to the limited history of prior indemnification claims and the unique facts and circumstances involved in each particular agreement. To date, the Company has not incurred any material costs as a result of such indemnifications and has not accrued any liabilities related to such obligations in these condensed financial statements.	7. Commitments and Contingencies Litigation From time to time, the Company may be involved in lawsuits, claims, investigations and proceedings, consisting of intellectual property, commercial, employment and other matters which arise in the ordinary course of business. The Company is not currently aware of any matters that would be material to the financial statements as a whole. Indemnifications In the ordinary course of business, the Company often includes standard indemnification provisions its arrangements with its partners, customer and suppliers. Pursuant to these provisions, the Company may be obligated to indemnify such parties for losses or claims suffered or incurred in connection with its service, breach of representations or covenants, intellectual property infringement or other claims made against such parties. These provisions may limit the time within which an indemnification claim can be made. It is not possible to determine the maximum potential amount under these indemnification obligations due to the limited history of prior indemnification claims and the unique facts and circumstances involved in each particular agreement. To date, the Company has not incurred any material costs as a result of such indemnifications and has not accrued any liabilities related to such obligations in these financial statements. Purchase Commitments As of December 31, 2019, the Company has obligations under non-cancellable

Term Loan

Term Loan	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Debt Disclosure [Abstract]
Term Loan	7. Term Loan Term loan consist of the following (in thousands): September 30, December 31, Principal of term loan $ 30,000 $ 30,000 Unamortized debt discount (348 ) (939 ) Total term loan 29,652 29,061 Less: term loan, current — (7,500 ) Term loan, noncurrent $ 29,652 $ 21,561 Perceptive Term Loans On June 30, 2017 the Company entered into a senior, secured, delayed-draw term loan facility (the “Perceptive Term Loan Agreement”) with Perceptive Credit Holdings, LP (the “Perceptive Lenders”), as the administrative agent and the collateral agent, for various related Perceptive group companies to borrow up to $40.0 million (the “Perceptive Term Loans”). The Perceptive Term Loans had a maturity date of June 30, 2021 and bore interest at a rate of 8.55% plus the greater of the three-month LIBOR and 2.00%. In July 2020, the Company used the SVB Term Loan (see below) to repay in full all amounts due under the Perceptive Term Loan and cash on hand to pay $1.2 million in early prepayment, accrued interest and exit fees. The repayment of the Perceptive Term Loan was accounted for as a debt extinguishment, which resulted in a loss on extinguishment of $1.6 million recorded in the accompanying condensed statements of operations for the nine months ended September 30, 2020. SVB Loan and Security Agreement On July 2, 2020, the Company entered into a senior secured term loan facility with Silicon Valley Bank (SVB) (the SVB Loan and Security Agreement), which provides for a $30.0 million term loan (the “SVB Term Loan”). The SVB Term Loan matures on November 1, 2025. Payments under the SVB Term Loan are for interest only through May 2023, and then 30 monthly principal and interest from June 2023 until maturity. The SVB Term Loan bears interest at the greater of (A) 0.5% above the Prime Rate as reported in the Wall Street Journal and (B) 3.75% (3.75% as of September 30, 2020). The Company is obligated to maintain a restricted cash balance greater or equal to the outstanding principal balance of $30.0 million of the SVB Term Loan. There is also a final payment fee equal to 6.75% of the original principal amount of the SVB Term Loan, or approximately $2.0 million, due at maturity (or any earlier date of optional pre-payment In the event of default or change in control, all unpaid principal and all accrued and unpaid interest amounts (if any) become immediately due and payable including the prepayment fee. Events of default include, but are not limited to, a payment default, a material adverse change, and insolvency. The SVB Term Loan is secured by substantially all of the Company’s assets, including all of the capital stock held by the Company, if any (subject to a 65% limitation on pledges of capital stock of foreign subsidiaries), subject to certain exceptions. The SVB Loan and Security Agreement contains customary representations, warranties, affirmative covenants and also contains certain restrictive covenants. Debt issuance costs paid directly to SVB and other debt issuance costs amounting to $0.4 million were accounted for as discounts on the SVB Term Loan as of September 20, 2020. These debt discounts, along with the final payment fee, are being amortized over the term of the SVB Term Loan using the effective interest rate method. As of September 30, 2020, the unamortized debt discount is $0.3 million, which is recorded as a direct deduction from the SVB Term Loan on the accompanying condensed balance sheet.	8. Term Loans Term loans consist of the following (in thousands): December 31, 2018 2019 Principal of Perceptive term loan $ 30,000 $ 30,000 Unamortized discount (1,654 ) (939 ) Term loan, current and noncurrent 28,346 29,061 Less: term loan, current — (7,500 ) Term loan, noncurrent $ 28,346 $ 21,561 Perceptive Term Loans On June 30, 2017 the Company entered into a senior, secured, delayed-draw term loan facility (the “Perceptive Term Loan Agreement”) with Perceptive Credit Holdings, LP (the “Perceptive Lenders”), as the administrative agent and the collateral agent, for various related Perceptive group companies to borrow up to $40.0 million (the “Perceptive Term Loans”). The Perceptive Term Loans bear interest at a rate of 8.55%, plus the greater of the three-month LIBOR and 2.00% (10.65% as of December 31, 2019) and may be drawn in two tranches. On the closing date, the first tranche, in the amount of $30.0 million (“Perceptive Term Loan A”), was drawn. The net proceeds of the Perceptive Term Loan A was approximately $29.5 million, net of an upfront fee of $0.3 million and closing costs. In connection with the Perceptive Term Loans, the Company issued warrants to the Perceptive Lenders for the purchase of up to an initial aggregate of 1,654,461 shares of the Company’s Series C redeemable convertible preferred stock, at an initial exercise price of $2.5915 per share. Of the total warrants issued, 1,240,846 were allocated to Perceptive Term Loan A and 413,615 were allocated to the second tranche (“Perceptive Term Loan B”) as the warrants were considered to have been issued in connection with the entire loan commitment. The fair value of the warrant on issuance was $3.0 million of which $2.2 million was recorded as a debt discount on Perceptive Term Loan A, and the remaining $0.8 million was recorded as a deferred loan commitment cost. The Company incurred debt financing costs on issuance of $0.7 million, of which $0.5 million was recorded as a debt discount on the Perceptive Term Loan A and the remaining amount of $0.2 million was recorded as a deferred loan commitment cost, which is being amortized over the remaining term of the term loan using the straight-line method. As of December 31, 2019, the deferred loan commitment cost was fully amortized. A final payment fee, in the amount of $0.3 million, or 1.1% of the principal amount of Perceptive Term Loan A, is being accreted to interest expense using the effective interest method with the offset recorded in other long-term liabilities. The fee represents incremental interest on Perceptive Term Loan A, which is due at maturity. On April 11, 2019, the Company and the Perceptive Lenders amended the Perceptive Term Loan Agreement in order to extend the Delayed Draw Date on Perceptive Term Loan B to March 31, 2020. The Term Loan B amount of $10.0 million had not been drawn as of December 31, 2019. The Company can borrow the Perceptive Term Loan B funds if the following conditions are achieved: (i) the borrowing shall occur on or prior to March 31, 2020 and (ii) the first commercial sale of the Company’s next generation product has occurred. The total amount of the Perceptive Term Loan B is up to $10.0 million, and is at the Company’s option. Payments relative to the Perceptive Term Loans are initially interest only and are made at the end of each calendar quarter. Principal payments of $3.8 million commence in the quarter ended September 30, 2020 and continue through March 31, 2021, with the remaining principal balance due on the maturity date of June 30, 2021; provided that if a Qualified IPO (as defined in the Perceptive Term Loan) occurs prior to June 30, 2020, the Company shall not be required to make any principal payments after the effective date of such Qualified IPO and the entire outstanding principal amount of the Perceptive Term Loans will be due on the maturity date of June 30, 2021. Other than for events of default and if a mandatory prepayment is required (see below), there are no requirements for the Company to repay a Perceptive Term Loan prior to maturity, although early repayments are permitted. In the event of an early repayment, if a Qualified IPO has not occurred on or prior to December 31, 2018, the Company is required to pay a fee in the amount of 6% of the aggregate outstanding principal if the Perceptive Term Loans are prepaid prior to the end of the first anniversary of the closing date, or June 30, 2018. The amount of the prepayment premium decreases by 1% during each subsequent twelve-month period thereafter, down to a minimum of 3%. As of December 31, 2019, the prepayment fee is 3% or $0.9 million. Mandatory prepayment of a Perceptive Term Loan is required upon the occurrence of a casualty event, which results in net cash proceeds in excess of $0.3 million in the aggregate to the Company an amount equal to (i) 100% of the net cash proceeds received by the Company, (ii) the applicable prepayment premium on the principal amount of the Perceptive Term Loans being so prepaid, (iii) any accrued but unpaid interest on such principal amount of the Perceptive Term Loans being so prepaid less, subject to certain conditions, (iv) costs to acquire or repair fixed or capital assets useful in the business. The Perceptive Term Loans are collateralized by a first priority security interest on substantially all of the Company’s assets excluding property not assignable without consent by a third party. Key Covenants The Company’s term loan agreement with Perceptive contains customary representations and warranties, covenants, events of default and termination provisions. The covenants place restrictions on the incurrence of additional indebtedness and liens, changes in the Company’s business, the payment of cash dividends, the dispositions of assets and mergers and acquisitions. Other covenants require the Company to maintain minimum cash balances and achieve certain annual minimum revenue targets. Revenue targets for the Perceptive term loan agreement will commence in the year ended December 31, 2019. The Company was in compliance with all covenants and limitations included in the provisions of its term loan agreement as of December 31, 2019. As of December 31, 2019, debt maturities for the next five years are as follows (in thousands): 2020 $ 7,500 2021 22,500 $ 30,000

Redeemable Convertible Preferre

Redeemable Convertible Preferred Stock and Stockholders' Deficit	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Equity [Abstract]
Redeemable Convertible Preferred Stock and Stockholders' Deficit	8. Redeemable Convertible Preferred Stock and Stockholders’ Equity (Deficit) Redeemable Convertible Preferred Stock Immediately prior to the closing of the Company’s IPO, all of the outstanding shares of redeemable convertible preferred stock converted into 25,958,000 shares of common stock, excluding the 274,000 shares of common stock that were issued on the exercise of outstanding redeemable convertible preferred stock warrants (see Note 9). Preferred Stock Upon the closing of the IPO, the Company’s amended and restated certificate of incorporation authorizes 5,000,000 shares of undesignated preferred stock, $0.001 par value per share, the rights, preferences and privileges of which may be designated from time to time by the Company’s board of directors. As of September 30, 2020, no shares of the preferred stock were issued and outstanding.	9. Redeemable Convertible Preferred Stock and Stockholders’ Deficit Redeemable Convertible Preferred Stock In August and November 2018, the Company issued a total of 43,352,179 shares of its Series D redeemable convertible preferred stock for $3.11 per share for net proceeds of $134.6 million. On September 17, 2019, the Company filed an amendment and restatement (the “Amendment”) of the Company’s Certificate of Incorporation (“COI”). The Amendment resulted in the cession of accrued dividends as of June 30, 2019, and the mandatory conversion of accrued dividends upon the close of the next equity financing with more than $50 million in proceeds. The Amendment also changed the conversion prices for each share of preferred stock from $7.9000, $17.9125, $20.4729 and $24.5690 for the Series A Preferred Stock, Series B Preferred Stock, Series C Preferred Stock and Series D Preferred Stock, respectively, to $10.5331, $19.9025, $20.4729 and $18.6124 for the Series A Preferred Stock, Series B Preferred Stock, Series C Preferred Stock and Series D Preferred Stock, respectively. The Company determined that the Amendment should be accounted for as an extinguishment of all Series of redeemable convertible preferred stock outstanding, which resulted in the Company recognizing a gain on extinguishment of $117.6 million on the Amendment date. The gain on the extinguishment of all outstanding Series of redeemable convertible preferred stock was calculated by taking the difference between the net carrying value of $415.1 million of all the outstanding redeemable convertible preferred stock immediately prior to the Amendment and the fair value of $297.5 million, net of issuance costs of $0.2 million, of the new Series of redeemable convertible preferred stock that for accounting purposes was deemed to be issued in connection with the Amendment. The gain on extinguishment was recorded as a decrease to net loss attributable to common stockholders for the year ended December 31, 2019 and as a decrease to accumulated deficit in stockholders’ deficit due to the absence of any additional paid-in Redeemable convertible preferred stock consists of the following (in thousands, except share and per share amounts): December 31, 2018 Shares Authorized Original Issue Shares Issued and Aggregate Carrying Series A 44,541,111 $ 1.0000 43,641,111 $ 74,493 $ 74,077 Series B 31,105,155 2.2674 28,929,196 87,580 87,276 Series C 32,946,219 2.5915 31,291,758 92,755 92,471 Series D 46,000,000 3.1100 43,352,179 138,719 138,460 154,592,485 147,214,244 $ 393,547 $ 392,284 December 31, 2019 Shares Authorized Original Issue Shares Issued and Aggregate Carrying Series A 44,541,111 $ 1.0000 43,641,111 $ 80,634 $ 77,503 Series B 31,105,155 2.2674 28,929,196 94,800 91,118 Series C 32,946,219 2.5915 31,291,758 100,401 96,502 Series D 46,000,000 3.1100 43,352,179 150,153 144,323 154,592,485 147,214,244 $ 425,988 $ 409,446 The Company has presented all of its Series A, Series B, Series C and Series D redeemable convertible preferred stock as temporary equity in its financial statements as the shares of stock contain redemption features that commence at any time on or after February 1, 2023 at the option of the holders. The Series A, Series B, Series C and Series D redeemable convertible preferred stock prior to the Amendment were initially recognized at their issuance date fair value, or transaction price. On the Amendment date, the Series A, Series B, Series C and Series D redeemable convertible preferred stock were recorded at their fair value. The Company adjusts the carrying amount of the Series A, Series B, Series C and Series D redeemable convertible preferred stock to equal its redemption value as of each reporting date. Due to the absence of retained earnings, adjustments to the redemption value are recorded as a reduction to additional paid-in-capital The significant rights, preferences and privileges of the redeemable convertible preferred stock is as follows: Dividend Rights Dividends for the holders of redeemable convertible preferred stock are cumulative and accrue at the rate of 8% per annum of the original issuance price, compounded quarterly until June 30, 2019. The accrued dividends will be automatically converted into shares of common stock if the Company raises net cash proceeds of at least $50.0 million, or a lesser amount if waived in writing by the holders of at least 66.66% of outstanding shares of redeemable convertible preferred stock. Subsequent to the Amendment, the holders of the redeemable convertible preferred stock are entitled to receive, on an as-converted Accrued Dividend Conversion Rights Subsequent to the Amendment, unless the dividends have already been paid or converted into shares of common stock, in the event of a next equity financing with cash proceeds of at least $50.0 million (“Next Equity Financing”), or a lesser amount if waived in writing by the holders of at least 66.66% of outstanding shares of redeemable convertible preferred stock, the $84.3 million of accrued dividends (“Accrued Dividend”) on the outstanding redeemable convertible preferred stock will automatically convert into shares of common stock. The number of shares issued on conversion will equal the quotient of (x) the amount of accrued dividends per share, divided by (y) quotient of (i) total proceeds in the Next Equity Financing divided by (ii) total number of shares of common stock issuable on the preferred stock issued in the Next Equity Financing. As of December 31, 2019, a Next Equity Financing has not occurred and the $84.3 million of Accrued Dividend are included in the redemption value of the redeemable convertible preferred stock. Voting Rights The holders of the majority of the outstanding shares of Series A redeemable convertible preferred stock, exclusively and as a separate class, shall be entitled to elect a majority of the directors of the Company, and the holders of the majority of the outstanding shares of Series D redeemable convertible preferred stock, exclusively and as a separate class, shall be entitled to elect one director of the Company. For all other matters, including the election of the remainder of the board of directors of the Company, the holders of redeemable convertible preferred stock have voting rights equivalent to the common stockholders and vote together with the common stockholders as a single class on an as-converted Conversion Rights The shares of Series A, Series B, Series C and Series D redeemable convertible preferred stock are convertible at any time, at the holders’ option, into shares of common stock. Prior to the Amendment, the conversion ratio is determined by dividing the Series A, Series B, Series C and Series D redeemable convertible preferred stock original issue price by the conversion price, which is set at $7.9000, $17.9125, $20.4729 and $24.5690 for the Series A, Series B, Series C and Series D redeemable convertible preferred stock, respectively. Subsequent to the Amendment, the conversion price is set at $10.5331, $19.9025, $20.4729 and $18.6124 for the Series A, Series B, Series C and Series D redeemable convertible preferred stock, respectively. These adjusted conversion prices result in conversion ratios of approximately 0.0949, 0.1139, 0.1266 and 0.1671 for the Series A, Series B, Series C and Series D redeemable convertible preferred stock, respectively, meaning that each share of Series A redeemable convertible preferred stock is convertible into approximately 0.0949 shares of common stock, each share of Series B redeemable convertible preferred stock is convertible into approximately 0.1139 shares of common stock, each share of Series C redeemable convertible preferred stock is convertible into 0.1266 share of common stock and each share of Series D redeemable convertible preferred stock is convertible into approximately 0.1671 shares of common stock. Adjustments to the conversion price, if any, occur if additional shares of common stock have been issued at a price less than the respective redeemable convertible preferred stock conversion price using the weighted average method. Mandatory Conversion The shares of redeemable convertible preferred stock will automatically convert to shares of common stock at the then applicable conversion rate upon either (a) the closing of the sale of shares of common stock to the public on the New York Stock Exchange, the NASDAQ Global Market or other internationally recognized stock exchange, in a firm-commitment underwritten public offering pursuant to an effective registration statement under the Securities Act of 1933, as amended, resulting in at least $40.0 million of proceeds before reduction for the underwriting discount, commissions and expenses to the Company and/or the selling stockholders at an offering price per share not less than $17.30 as adjusted for any stock dividend, stock split, combination of shares, reorganization, recapitalization, or other similar event with respect to the common stock or (b) with respect to each series of redeemable convertible preferred stock, upon election of the holders representing a majority of the then outstanding shares of such series. In connection with the automatic conversion, the holders of Series A, Series B, Series C and Series D redeemable convertible preferred stock will be converted to shares of common stock, at the applicable conversion rate. Liquidation Preference Prior to the Amendment, in the event of any voluntary or involuntary liquidation, dissolution or winding up of the Company, the holders of Series A, Series B, Series C and Series D redeemable convertible preferred stock are entitled to receive, on a pari passu basis, and before any payment shall be made to the holders of common stock a per share amount equal to the original issue price of $1.00, $2.2674, $2.5915 and $3.11, respectively, plus any accrued but unpaid dividend for the Series A, Series B, Series C and Series D redeemable convertible preferred stock subject to adjustment for recapitalizations, stock dividends or the like, together with all declared but unpaid dividend, if any. Subsequent to the Amendment, in the event of any voluntary or involuntary liquidation, dissolution or winding up of the Company, the holders of Series A, Series B, Series C and Series D redeemable convertible preferred stock are entitled to receive, on a pari passu basis, and before any payment shall be made to the holders of common stock a per share amount equal to the greater of (a) original issue price or (b) the sum of the applicable accrued dividends per share, plus the amount per share as would have been payable had all shares of such series of preferred stock been converted into shares of common stock. As of December 31, 2019, the liquidation preference was determined under criterion (b) and was the sum of the applicable accrued dividends per share, plus the amount per share as would have been payable had all shares of such series of preferred stock been converted into shares of common stock. If the assets of the Company are insufficient to pay the holders of redeemable convertible preferred stock the full amount, the holders of Series A, Series B, Series C and Series D redeemable convertible preferred stock will share ratably in any distribution of the assets available for distribution in proportion to the respective amounts of their liquidation preferences. If preferential amounts are paid in full, the remaining assets of the Company are distributed among the holders of redeemable convertible preferred stock and common stock pro rata based on the number of shares held by each shareholder. Redemption Rights Series A, Series B and Series C redeemable convertible preferred stock At any time and from time to time on or after February 1, 2023, upon written notice from the holders of at least a majority of the then outstanding shares of Series A redeemable convertible preferred stock (a “Redemption Request”), all of the shares of Series A, Series B and Series C redeemable convertible preferred stock shall be redeemed by the Company. Prior to the Amendment, the redemption value was for cash at a price equal to the original issue price, less the per share amount repaid, plus any dividends accrued, but unpaid, whether or not declared, together with any other dividends declared but unpaid in three equal annual installments starting with the first payment no later than thirty days following the receipt by the Company a Redemption Request. Subsequent to the Amendment, the redemption value is for cash at a price equal to the original issue price, less the per share amount repaid, plus unpaid Accrued Dividends of $74.8 million, but unpaid, whether or not declared, together with any other dividends declared but unpaid in three equal annual installments starting with the first payment no later than thirty days following the receipt by the Company a Redemption Request. Series D redeemable convertible preferred stock At any time and from time to time on or after February 1, 2023, upon written notice from the holders of at least a majority of the then outstanding shares of Series A redeemable convertible preferred stock and at least a majority of the then outstanding shares of Series D redeemable convertible preferred stock, voting as separate classes (a “Series D Redemption Request”) all of the shares of Series D redeemable convertible preferred stock shall be redeemed by the Company. Prior to the Amendment, the redemption value was for cash at a price equal to the original issue price, less the per share amount repaid, plus any dividends accrued, but unpaid, whether or not declared, together with any other dividends declared but unpaid in three equal annual installments starting with the first payment no later than thirty days following the receipt by the Company a Series D Redemption Request. Subsequent to the Amendment, the redemption value was for cash at a price equal to the original issue price, less the per share amount repaid, plus Accrued Dividend of $9.5 million, but unpaid, whether or not declared, together with any other dividends declared but unpaid in three equal annual installments starting with the first payment no later than thirty days following the receipt by the Company a Series D Redemption Request. Common Stock The Company has reserved shares of common stock, on an as-if December 31, 2018 2019 Redeemable convertible preferred stock 18,634,636 18,643,769 Warrants to purchase redeemable convertible preferred stock 598,785 504,791 Warrants to purchase common stock 8,860 — Options issued and outstanding 3,310,990 3,757,457 Options available for grant under stock option plan 639,442 195,439 23,192,713 23,101,456

Redeemable Convertible Prefer_2

Redeemable Convertible Preferred Stock Warrants and Common Stock Warrants	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Equity [Abstract]
Redeemable Convertible Preferred Stock Warrants and Common Stock Warrants	9. Redeemable Convertible Preferred Stock Warrants and Common Stock Warrants On the closing of the IPO, the aggregate outstanding Series A redeemable convertible preferred stock warrants of 500,000 shares converted into 63,000 common stock warrants with an exercise price of $7.96 per share. The common stock warrants expire in September 2025. On the closing of the IPO, the aggregate outstanding Series B redeemable convertible preferred stock warrants of 2,176,000 shares were net exercised with an exercise price of $2.2674 per share, which resulted in the issuance of 65,000 shares of the Company’s common stock based on the IPO price of $27.00 per share. In addition, the aggregate outstanding Series C redeemable convertible preferred stock warrants of 1,655,000 shares were cash exercised at an exercise price of $2.5915 per share, which resulted in the issuance of 209,000 shares of the Company’s common stock with total aggregate cash proceeds of $4.3 million. As of September 30, 2020, there were no preferred stock warrants outstanding.	10. Redeemable Convertible Preferred Stock Warrants and Common Stock Warrants Redeemable Convertible Preferred Stock Warrants The key terms of the outstanding warrants to purchase redeemable convertible preferred stock are summarized in the following table: December 31, Class of Stock Exercise Grant Date Expiration Date 2018 2019 Series A redeemable convertible preferred stock $ 1.0000 July 2012 July 2019 400,000 — Series A redeemable convertible preferred stock 1.0000 September 2013 September 2023 1) 300,000 300,000 Series A redeemable convertible preferred stock 1.0000 September 2014 September 2024 1) 200,000 200,000 Series B redeemable convertible preferred stock 2.2674 September 2015 September 2025 2,109,804 2,109,804 Series B redeemable convertible preferred stock 2.2674 June 2016 June 2026 66,155 66,155 Series C redeemable convertible preferred stock 2.5915 June 2017 June 2027 1,654,461 1,654,461 4,730,420 4,330,420 1) The redeemable convertible preferred stock warrants expire at the later of the expiration date, or five years after an initial public offering by the Company. In July 2019, the warrant to purchase 400,000 shares of Series A redeemable convertible preferred stock expired unexercised. The following table sets forth the estimated fair value for each issuance of the Company’s warrants to purchase redeemable convertible preferred stock as of December 31, 2018 and 2019 (in thousands): December 31, Class of Warrants 2018 2019 2013 warrant to purchase Series A redeemable convertible preferred stock $ 397 $ 157 2014 warrant to purchase Series A redeemable convertible preferred stock 275 121 2015 warrant to purchase Series B redeemable convertible preferred stock 3,879 1,879 2016 warrant to purchase Series B redeemable convertible preferred stock 129 64 2017 warrant to purchase Series C redeemable convertible preferred stock 3,405 2,064 $ 8,085 $ 4,285 The warrants to purchase redeemable convertible preferred stock were valued using the Black-Scholes option-pricing model at the issuance date and remeasured using the following assumptions: Years Ended December 31, 2018 2019 Market value of shares of redeemable convertible preferred stock $2.05 - $3.25 $1.36 - $2.40 Expected term (in years) 4.74 - 8.50 3.74 - 7.50 Expected volatility 48.8% - 50.1% 48.1% - 50.0% Risk-free interest rate 2.51% - 2.59% 1.76% - 1.83% Dividend yield 0% 0% Common Stock Warrants In 2009, the Company issued a warrant to purchase 8,860 shares of common stock with a fair value of $30,000 in connection with a product development agreement. The warrant has been included in stockholders’ deficit as additional paid-in

Stock-based Compensation

Stock-based Compensation	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Share-based Payment Arrangement [Abstract]
Stock-based Compensation	10. Stock-based Compensation Equity Incentive Plans In September 2020, the Company adopted the 2020 Equity Incentive Plan (the “2020 Plan”), which became effective in connection with the IPO. As a result, the Company may not grant any additional awards under the 2010 and 2019 Plans (the “Prior Plans”). The Prior Plans will continue to govern outstanding equity awards previously granted thereunder. The Company has initially reserved 3,665,000 shares of common stock for the issuance of awards under the 2020 Plan. In addition, the number of shares of common stock available under the Plan shall increase annually on the first day of each fiscal year, commencing January 2021, and continuing until (and including) the fiscal year ending December 31, 2030, with such annual increase equal to an amount equal to the lesser of (i) 4% of the number of shares of common stock issued and outstanding on December 31 of the immediately preceding calendar year, and (ii) an amount determined by the Company’s board of directors. No awards were granted under the 2020 Plan in September 2020. Options under the 2020 Plan have a contractual term of 10 years. The exercise price of an option shall not be less than 100% of the fair market value of the shares on the date of grant. Employees Share Purchase Plan (ESPP) In September 2020, the Company adopted the Employee Share Purchase Plan (ESPP). The Company has initially reserved 687,000 shares of common stock for purchase under the ESPP. In addition, the number of shares of common stock available for issuance under the ESPP will automatically increase on the first trading day in January of each calendar year, commencing January 2021, by an amount equal to the lesser of (i) 687,000 shares, (ii) 1% of the number of common stock issued and outstanding on December 31 of the immediately preceding fiscal year, and (iii) an amount determined by the Company’s board of directors. Subject to any limitations contained therein, the ESPP allows eligible participants to contribute, through payroll deductions, 15% of their eligible compensation to purchase the Company’s common stock at equal to 85% of the fair market value of the common stock on the first day of the offering period or purchase date, whichever is lower. The ESPP generally provides for consecutive, overlapping 6-month Stock-Based Compensation The following table sets forth stock-based compensation included in the accompanying condensed statements of operations (in thousands): Nine Months Ended 2020 2019 Cost of revenue $ 181 $ 3 Research and development 3,326 266 Sales and marketing 2,828 119 General and administrative 8,836 248 Total stock-based compensation expense 15,171 636 Stock Options with Market and Performance Conditions As of September 30, 2020, the Company has 1,944,000 shares of stock options outstanding to employees and executive officers. with performance and market-based vesting conditions. The options vest over the requisite service period if the Company achieves both (i) a performance condition tied to a liquidity event, which includes the effectiveness of an IPO, and (ii) certain market conditions, provided the optionee is providing services on the date of the event. In February 2020, the Company modified the market conditions, which resulted in a new grant date fair value for 1,457,000 stock options with performance and market-based conditions as of the modification date. For the nine months ended September 30, 2020, the Company recorded cumulative stock-based compensation of $13.4 million related to all outstanding stock options with performance and market-based vesting conditions as the performance vesting condition was satisfied upon the closing of the IPO. As of September 30, 2020, 152,000 shares of these options were fully vested. Unamortized stock-based compensation amounted to $10.0 million as of September 30, 2020, which the Company expects to recognize over an estimated weighted-average period of 0.4 years.	11. Equity Incentive Plan During 2019, the Company’s board of directors voted to terminate the 2010 Plan and no additional stock options may be granted under the 2010 Plan. However, all outstanding stock options granted pursuant to the 2010 Plan will continue to be subject to terms and conditions of the 2010 Plan. The Company’s board of directors approved and established the 2019 Equity Incentive Plan (the “2019 Plan”) for the purpose of providing incentive and non-statutory non-employees. 10-year non-qualified The 2019 Plan allows, and the Company has granted awards which vest either: over time, upon certain corporate-based performance, or upon certain corporate-based performance concurrent with a market condition. Stock Option Activity Stock option activity under the 2010 Plan was as follows: Options Available Number of Weighted Weighted Aggregate Balance as of December 31, 2018 639,442 3,310,990 $ 3.36 8.16 $ 2,490 Additional shares authorized 126,582 — Granted (937,484 ) 937,484 $ 5.62 Exercised — (124,118 ) $ 2.92 Cancelled and forfeited 366,899 (366,899 ) $ 3.24 Balance as of December 31, 2019 195,439 3,757,457 $ 3.95 7.81 $ 8,618 Vested and expected to vest as of December 31, 2019 3,603,449 $ 3.95 7.76 $ 8,396 Exercisable as of December 31, 2019 1,361,219 $ 1.34 6.16 $ 4,697 The total intrinsic value of options exercised during the years ended December 31, 2018 and 2019 was $0.1 million and $0.2 million, respectively. The intrinsic value is the difference between the estimated fair value of the Company’s common stock at the time of exercise, as determined by the board of directors, and the exercise price of the stock option. Determining Fair Value Stock Options Granted to Employees with Service-Based Vesting The weighted average grant date fair value of options granted to employees was $1.90 and $2.77 per share during the years ended December 31, 2018 and 2019, respectively. The total fair value of options that vested during the years ended December 31, 2018 and 2019 was $0.7 million and $0.7 million, respectively. The fair value of an employee stock option is estimated on the date of grant using the Black-Scholes option-pricing model and the assumptions discussed below. Each of these inputs is subjective and generally requires significant judgment. Fair Value of Common Stock Expected Term mid-point Expected Volatility Risk-Free Interest Rate Dividend Yield The following ranges of assumptions were used to value options with service-based and/or performance vesting granted to employees: Years Ended December 31, 2018 2019 Expected term (in years) 4.78 - 4.98 4.97 - 5.05 Expected volatility 48.4% - 48.8% 49.3% - 50.9% Risk-free interest rate 2.65% - 3.02% 1.57% - 2.48% Dividend yield 0% 0% Stock-based Compensation The following table sets forth stock-based compensation included in the Company’s statements of operations (in thousands): Years Ended December 31, 2018 2019 Cost of revenue $ 14 $ 5 Research and development 234 227 Sales and marketing 176 189 General and administrative 364 462 Total stock-based compensation $ 788 $ 883 As of December 31, 2019, there was $0.8 million of unrecognized compensation cost related to stock-based compensation arrangements granted under the 2010 Plan. That cost is expected to be recognized over a weighted average period of 0.67 years. Stock Options with Performance and Market Conditions During the years ended December 31, 2018 and December 31, 2019, the Company issued 321,268 and 632,064 shares of stock options with performance and market-based conditions to employees and executive officers, respectively. The awards will vest over the requisite service period if the Company achieves both (i) a liquidity event, which includes the effectiveness of an IPO and (ii) certain market conditions, provided the optionee is providing services on the date of the event. As the achievement of the performance condition was not considered probable as of December 31, 2019, no associated expense was recognized during the years ended December 31, 2018 and 2019. Unamortized deferred stock-based compensation relating to the performance and market-based conditions amounted to $18.7 million as of December 31, 2019. As of December 31, 2019, all compensation related to these stock options remained unrecognized because as of those dates the Company did not believe either of the liquidity events were probable of occurring.

Income Taxes

Income Taxes	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Income Taxes	11. Income Taxes For the nine months ended September 30, 2020 and 2019, the Company incurred insignificant amounts for an income tax provision. The U.S. federal and California deferred tax assets generated from the Company’s net operating losses have been fully reserved, as the Company believes it is not more likely than not that the benefit will be realized.	12. Income Taxes The Company had state income tax expense of $20,000 and $25,000 for the years ended December 31, 2018 and 2019, respectively. The Company has incurred net operating losses for all periods presented. The Company has not reflected any benefit of such net operating loss carryforwards in the accompanying financial statements. The Company has established a full valuation allowance against its deferred tax assets due to the uncertainty surrounding the realization of such assets. The effective tax rate of the provision for income taxes differs from the federal statutory rate as follows: Years Ended December 31, 2018 2019 Federal statutory income tax rate 21.0 % 21.0 % State taxes 4.9 7.8 Change in valuation allowance (27.2 ) (28.5 ) Federal and state tax credits 2.0 0.9 Other (0.7 ) (1.2 ) — % — % Deferred Tax Assets and Liabilities The components of the deferred tax assets and liabilities are as follows (in thousands): December 31, 2018 2019 Deferred tax assets: Net operating loss carryforwards $ 43,405 $ 56,127 Tax credits 6,993 8,777 Accrual and reserves 1,126 1,675 Tangible and intangible assets 7,117 15,888 Stock-based compensation 551 733 Gross deferred tax assets 59,192 82,865 Valuation allowance (59,192 ) (82,865 ) Net deferred tax assets $ — $ — Deferred tax liabilities: Other intangibles $ — $ — Net deferred tax $ — $ — Realization of the deferred tax assets is dependent upon future taxable income, if any, the amount and timing of which are uncertain. The Company has established a valuation allowance to offset deferred tax assets as of December 31, 2018 and 2019 due to the uncertainty of realizing future tax benefits from its net operating loss carryforwards and other deferred tax assets. The valuation allowance increased by approximately $13.6 million and by approximately $23.7 million during the years ended December 31, 2018 and 2019, respectively. Net Operating Loss and Tax Credit Carryforwards As of December 31, 2019, the Company had a net operating loss carryforward for federal income tax purposes of approximately $210.8 million. Federal net operating losses of $83.0 million incurred after 2017 do not expire. The remaining $127.8 million of federal net operating loss carryforward will begin to expire in 2024 and continue to expire through 2037. The Company had a total state net operating loss carryforward of approximately $141.6 million. State net operating losses of $8.2 million do not expire. The remaining state net operating loss carryforward of $133.5 million will begin to expire in 2020 and continue to expire through 2040. Federal and state laws impose substantial restrictions on the utilization of net operating loss and tax credit carryforwards in the events of an ownership change for tax purposes, as defined in Section 382 of the Internal Revenue Code. As a result of such ownership changes, the Company’s ability to realize the potential future benefit of tax losses and tax credits that existed at the time of the ownership change may be significantly reduced. The Company’s deferred tax asset and related valuation allowance would be reduced, as a result. The Company has not performed a Section 382 study to determine the amount of reduction, if any. Unrecognized tax benefits at December 31, 2019 have been recorded as an offset to federal and state research and development credit carryforwards. Unrecognized Tax Benefits A reconciliation of the total unrecognized tax benefits for the year ended December 31, 2019 is as follows (in thousands): Balance, beginning of year $ 8,385 Decrease related to current year positions (7,601 ) Increase related to current year positions 236 Balance, end of year $ 1,020 The Company does not have any material accrued interest or penalties associated with unrecognized tax benefits. The Company does not believe it is reasonably possible that its unrecognized tax benefits will significantly change within the next twelve months. The Company files income tax returns in the United States and various states. The Company is not currently under examination by income tax authorities in federal, state or other jurisdictions. All tax returns remain open for examination by federal and state authorities for three and four years, respectively, from the date of utilization of any net operating loss or credits.

Related-Party Transactions

Related-Party Transactions	12 Months Ended
	Dec. 31, 2019
Related Party Transactions [Abstract]
Related-Party Transactions	13. Related-Party Transactions The Company incurred approximately $0.4 million and $0.3 million of operating expenses with related parties during the years ended December 31, 2018 and 2019, respectively. As of December 31, 2018, and 2019, the Company had $1,000 and $0, respectively, of amounts payable to related parties. The expenses were primarily related to consulting fees and expense reimbursements paid to certain directors of the Company.

Net Loss per Share Attributable

Net Loss per Share Attributable to Common Stockholders	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Earnings Per Share [Abstract]
Net Loss Per Share Attributable to Common Stockholders	12. Net Loss Per Share Attributable to Common Stockholders A reconciliation of the numerator and denominator used in the calculation of basic and diluted net loss per share attributable to common stockholders is as follows (in thousands except per share amounts): Nine Months Ended 2020 2019 Numerator: Net loss $ (89,449 ) $ (48,853 ) Adjustment to redemption value on redeemable convertible preferred stock (362 ) (134,760 ) Deemed dividend on settlement of accrued dividend 42,530 — Gain on extinguishment of redeemable convertible preferred stock — 117,598 Net loss attributable to common stockholders, basic and diluted $ (47,281 ) $ (66,015 ) Denominator: Weighted-average shares of common stock, basic and diluted 7,508 838 Net loss per share attributable to common stockholders, basic and diluted $ (6.30 ) $ (78.77 ) The following outstanding potentially dilutive shares were excluded from the calculation of diluted net loss per share due to their anti-dilutive effect (in thousands): Nine Months Ended 2020 2019 Redeemable convertible preferred stock, on an as-if — 18,644 Options to purchase common stock 4,742 3,852 Warrants to purchase redeemable convertible preferred stock — 505 Warrant to purchase common stock 63 — Shares committed under ESPP 5 — Total 4,810 23,001	14. Net Loss per Share Attributable to Common Stockholders The following outstanding potentially dilutive shares have been excluded from the calculation of diluted net loss per share due to their anti-dilutive effect: Years Ended December 31, 2018 2019 Redeemable convertible preferred stock on an as-if 18,634,636 18,643,769 Options to purchase common stock 3,310,990 3,757,457 Warrants to purchase redeemable convertible preferred stock 598,785 504,791 Warrants to purchase common stock 8,860 — Total 22,553,271 22,906,017

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2019
Subsequent Events [Abstract]
Subsequent Events	15. Subsequent Events A. Redeemable Convertible Preferred Stock Financing During the first quarter of 2020, the Company completed a financing of its Series E redeemable convertible preferred stock, in which the Company issued 57,781,875 shares of Series E redeemable convertible preferred stock at a price per share of $2.20 for aggregate proceeds of $127.1 million. Immediately following the closing of the Series E financing, the Company issued 4,849,933 shares of its common stock in settlement of the Accrued Dividend Conversion Right (see Note 9 for further details) of $84.3 million. B. Manufacturing Facility Lease In May 2020, the Company entered into an operating lease agreement for its new facility space in Tijuana, Mexico that will commence in May 2020 and will expire in August 2026. The Company will take initial possession of the building with 48,437 square feet in May 2020 and the second space with 38,750 square feet in June 2021. This operating lease contains a free rent period and an escalation clause. The Company issued an irrevocable standby letter of credit in the amount of $1.7 million, in lieu of a cash security deposit. In addition, the Company agreed to spend approximately $3.5 million by March 2021 to renovate the first space, and another $3.5 million by December 2023 to renovate the second space. The letter of credit is fully secured by cash held at the bank in a restricted account. The total future minimum lease payments associated with this operating lease agreement are approximately $3.2 million plus operating expenses. C. Reverse Stock Split In September 2020, the Company’s board of directors approved an amended and restated certificate of incorporation to effect a reverse split of shares of the Company’s common stock on a 7.9-for-one

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying condensed financial statements are unaudited and have been prepared in accordance with U.S. generally accepted accounting principles (U.S. GAAP) and on the same basis as the annual financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments, that are necessary for the fair statement of the Company’s financial position, results of operations, comprehensive loss and cash flows for the interim periods presented. The financial data and the other financial information disclosed in these notes to the condensed financial statements related to the nine-month periods are also unaudited. The results of operations for the nine months ended September 30, 2020 are not necessarily indicative of the results of operations to be anticipated for any other future annual or interim period. The condensed balance sheet as of December 31, 2019 included herein was derived from the audited financial statements as of that date. These unaudited condensed financial statements should be read in conjunction with the Company’s audited financial statements and related notes for the year ended December 31, 2019, which are included elsewhere in this prospectus. All share amounts disclosed in the notes to the condensed financial statements are rounded to the nearest thousand except for per share data.	Basis of Presentation The Company’s financial statements have been prepared in accordance with United States generally accepted accounting principles (“U.S. GAAP”).
Use of Estimates	Use of Estimates The preparation of the accompanying condensed financial statements in conformity with U.S. GAAP requires management to make judgments, estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities as of the date of the accompanying condensed financial statements and the reported amounts of revenue and expenses. These judgments, estimates and assumptions are used for, but not limited to, revenue recognition, allowance for doubtful accounts, inventory valuation and write-downs, warranty obligations, the fair value of common stock and redeemable convertible preferred stock, the fair value of stock options, the fair value of the redeemable convertible preferred stock warrant liability, valuation of investments, recoverability of the Company’s net deferred tax assets and the related valuation allowance, and certain accrued expenses. The Company evaluates its estimates and assumptions on an ongoing basis using historical experience and other factors and adjusts those estimates and assumptions when facts and circumstances dictate. Actual results may differ from those estimates under different assumptions or conditions and the differences may be material.	Use of Estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make judgements, estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities as of the date of the financial statements and the reported amounts of revenue and expenses. These judgements, estimates and assumptions are used for, but not limited to, revenue recognition, allowance for doubtful accounts, inventory valuation and write-downs, warranty obligations, fair value of common stock and redeemable convertible preferred stock, the fair value of stock options, the fair value of redeemable convertible preferred stock warranty liability, valuation of investments, recoverability of the Company’s net deferred tax assets and the related valuation allowance, and certain accrued expenses. The Company evaluates its estimates and assumptions on an ongoing basis using historical experience and other factors and adjusts those estimates and assumptions when facts and circumstances dictate. Actual results may differ from those estimates under different assumptions or conditions and the differences may be material.
Segment		Segment The Company operates as a single operating segment. The Company’s chief operating decision maker, its Chief Executive Officer, reviews financial information on an aggregate basis for the purposes of allocating resources and evaluating financial performance. The Company has only operated in the United States since its inception and has derived its revenue from sales to customers in the United States.
Cash, Cash Equivalents and Restricted Cash	Cash, Cash Equivalents and Restricted Cash As of September 30, 2020, the restricted cash balance of $33.3 million primarily relates to contractual obligations under the SVB Loan and Security Agreement (see Note 7) and collateral for the building leases in San Jose, CA and Tijuana Mexico. The restricted cash balance of $0.7 million as of December 31, 2019 relates to collateral for the building leases. The following table provides a reconciliation of cash, cash equivalents and restricted cash that sum to the total of the amounts shown in the accompanying condensed statements of cash flows (in thousands): September 30, 2020 2019 Cash and cash equivalents $ 311,327 $ 39,216 Restricted cash 33,311 743 Total cash, cash equivalents and restricted cash $ 344,638 $ 39,959	Cash, Cash Equivalents and Restricted Cash The Company considers all highly liquid investments purchased with an original maturity of three months or less at the date of purchase to be cash equivalents. As of December 31, 2018 and 2019, the Company’s cash equivalents were held in institutions in the United States and include deposits in a money market fund which were unrestricted as to withdrawal or use. As of December 31, 2018 and 2019, the Company had restricted cash of $0.2 million and $0.7 million, respectively, representing collateral for the Company’s building leases in San Jose, CA. Restricted cash is classified in other assets in the accompanying balance sheets. The following table provides a reconciliation of cash, cash equivalents and restricted cash reported within the balance sheets that sum to the total of the amounts shown in the statements of cash flows: December 31, 2018 2019 Cash and cash equivalents $ 33,264 $ 36,926 Restricted cash 151 743 $ 33,415 $ 37,669
Investments		Investments The Company classifies its investment securities as available-for-sale. A decline in the fair value of any security below cost that is deemed other than temporary results in a charge to earnings and the corresponding establishment of a new cost basis for the security. Premiums (discounts) are amortized (accreted) over the life of the related security as an adjustment to yield using the straight-line interest method. Dividend and interest income are recognized when earned. Realized gains and losses are included in earnings and are derived using the specific identification method for determining the cost of securities sold.
Fair Value of Financial Instruments	Fair Value of Financial Instruments The Company determines the fair value of an asset or liability based on the assumptions that market participants would use in pricing the asset or liability in an orderly transaction between market participants at the measurement date. The identification of market participant assumptions provides a basis for determining what inputs are to be used for pricing each asset or liability. A fair value hierarchy has been established which gives precedence to fair value measurements calculated using observable inputs over those using unobservable inputs. This hierarchy prioritizes the inputs into three broad levels as follows: Level 1: Quoted prices in active markets for identical instruments; Level 2: Other significant observable inputs (including quoted prices in active markets for similar instruments); and Level 3: Significant unobservable inputs (including assumptions in determining the fair value of certain investments). The Company’s cash and cash equivalents, restricted cash, short-term investments, accounts receivable, accounts payable and accrued liabilities approximate their fair value due to their short maturities. Management believes that its term loan bears interest at the prevailing market rates for instruments with similar characteristics; accordingly, the carrying value of this instrument approximates its fair value. Money market funds are highly liquid investments and are actively traded. The pricing information on the Company’s money market funds are readily available and can be independently validated as of the measurement date. This approach results in the classification of these securities as Level 1 of the fair value hierarchy. The Company has issued redeemable convertible preferred stock warrants and estimated the fair value of these warrants using the Black-Scholes option pricing model, which is considered to be a Level 3 fair value measurement. The assumptions that were based on the individual characteristics of the warrants on the valuation date, as well as assumptions for future financings, expected volatility, expected life, yield, and risk-free interest rate. Effective on the date of the IPO, the redeemable convertible preferred stock warrants were considered to be indexed to the Company’s stock, and accordingly, the fair value of redeemable convertible preferred stock warrant liability was remeasured immediately prior to the IPO (See Note 4).	Fair Value of Financial Instruments The Company determines the fair value of an asset or liability based on the assumptions that market participants would use in pricing the asset or liability in an orderly transaction between market participants at the measurement date. The identification of market participant assumptions provides a basis for determining what inputs are to be used for pricing each asset or liability. A fair value hierarchy has been established which gives precedence to fair value measurements calculated using observable inputs over those using unobservable inputs. This hierarchy prioritized the inputs into three broad levels as follows: Level 1: Quoted prices in active markets for identical instruments; Level 2: Other significant observable inputs (including quoted prices in active markets for similar instruments); and Level 3: Significant unobservable inputs (including assumptions in determining the fair value of certain investments). The Company’s cash and cash equivalents, restricted cash, accounts receivable, accounts payable and accrued liabilities approximate their fair value due to their short maturities. Management believes that its term loan bears interest at the prevailing market rates for instruments with similar characteristics; accordingly, the carrying value of this instrument approximates its fair value. Money market funds are highly liquid investments and are actively traded. The pricing information on the Company’s money market funds are readily available and can be independently validated as of the measurement date. This approach results in the classification of these securities as Level 1 of the fair value hierarchy. There were no transfers between Levels 1, 2 or 3 for any of the periods presented. The Company has issued redeemable convertible preferred stock warrants for which fair value is determined using Level 3 inputs (see Note 4).
Concentration of Credit Risk		Concentration of Credit Risk Financial instruments that potentially subject the Company to a concentration of credit risk consist of cash and cash equivalents, restricted cash, short-term investments and accounts receivable. Substantially all the Company’s cash and cash equivalents, restricted cash and investments are held at one financial institution in the United States that management believes is of high credit quality. Such deposits may, at times, exceed federally insured limits or may not be covered by deposit insurance at all. The Company has not experienced any credit losses on its cash and cash equivalents, restricted cash or short-term investments through December 31, 2019. Four customers accounted for 20%, 18%, 14% and 12% of revenues, respectively, in the year ended December 31, 2018. One customer accounted for 11% of revenues in the year ended December 31, 2019. Accounts receivable are unsecured and the Company does not require collateral; however, the Company does assess the collectability of accounts receivable based on a number of factors, including past transaction history with, and the creditworthiness of, the customer. Accordingly, the Company is exposed to credit risk associated with accounts receivable. Four customers accounted for 28%, 24%, 16% and 12% of accounts receivable, respectively, as of December 31, 2018. Four customers accounted for 22%, 13%, 11% and 10% of accounts receivable, respectively, as of December 31, 2019. To reduce risk, the Company closely monitors the amounts due from its customers and assesses the financial strength of its customers through a variety of methods that include, but are not limited to, engaging directly with customer operations and leadership personnel, visiting customer locations to observe operating activities, and assessing customer longevity and reputation in the marketplace. As a result, the Company believes that its accounts receivable credit risk exposure is limited. The Company provides for uncollectible amounts when specific credit problems are identified. As of December 31, 2018, the Company did not have an allowance for doubtful accounts. As of December 31, 2019, the Company recorded an allowance for doubtful accounts of $59,000.
Inventories		Inventories Inventories are stated at the lower of cost or net realizable value. Cost is determined using the standard cost method, which approximates actual costs as determined on a first-in, first-out
Property and Equipment, Net		Property and Equipment, Net Property and equipment, net is stated at cost, net of accumulated depreciation. Depreciation is computed using the straight-line method based on the estimated useful lives of the assets, which is generally two to five years. Leasehold improvements are amortized using the straight-line method over the shorter of the assets estimated useful lives or the remaining term of the lease. Maintenance and repairs are charged to expense as incurred. Significant improvements that substantially enhance the useful life of an asset are capitalized and depreciated. When assets are retired or disposed of, the cost together with related accumulated depreciation is removed from the balance sheet and any resulting gain or loss is reflected in the Company’s statements of operations in the period realized.
Leases		Leases The Company accounts for its lease arrangements in accordance with FASB Accounting Standards Codification (“ASC”) Topic 842, Leases right-of-use ROU assets represent the Company’s right to use an underlying asset for the lease term and lease liabilities represent the Company’s obligation to make lease payments arising from the lease. Operating lease ROU assets and liabilities are recognized based on the present value of lease payments over the lease term at commencement date of the lease. ROU assets also include any initial direct costs incurred and any lease payments made at or before the lease commencement date, less any lease incentive received. As most of the Company’s leases do not provide an implicit interest rate, the Company uses its incremental borrowing rate based on the information available at the commencement date in determining the present value of lease payments. The Company uses the implicit rate when readily determinable. The Company’s lease terms may include options to extend or terminate the lease when it is reasonably certain that the Company will exercise that option. Lease expense for lease payments is recognized on a straight-line basis over the lease term. The Company does not recognize a ROU asset nor lease liability for short-term leases. Instead, it recognizes these short-term lease payments in the income statement on a straight-line basis over the lease term. Short-term leases are defined as 12 months or less in duration.
Impairment for Long-Lived Assets		Impairment for Long-Lived Assets Long-lived assets, such as property and equipment are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. If circumstances require a long-lived asset or asset group to be tested for possible impairment, the Company first compares undiscounted cash flows expected to be generated by that asset or asset group to its carrying value. If the carrying value of the long-lived asset or asset group is not recoverable on an undiscounted cash flow basis, an impairment is recognized to the extent that the carrying value exceeds its fair value. Fair value is determined through various valuation techniques including discounted cash flow models, quoted market values and third-party independent appraisals, as considered necessary. There were no such impairment losses as of December 31, 2018 and 2019.
Deferred Loan Commitment Costs		Deferred Loan Commitment Costs Costs incurred to obtain term loan commitments (see Note 8) are recorded in other assets and amortized to interest expense over the term of the commitment on a straight-line basis. When amounts are borrowed under a loan commitment in the future, a proportionate amount of the remaining unamortized deferred cost will be reclassified as a debt discount and amortized over the remaining term of the term loan using the effective interest method. If a commitment for a term loan expires unused, the related balance is charged to interest expense. As of December 31, 2018, the total unamortized deferred loan commitment costs recorded in other assets amounted to $0.1 million. As of December 31, 2019, there was no unamortized deferred loan commitment balance.
Accrued Warranty Liability	Accrued Warranty Liability The Company generally provides a one-year	Accrued Warranty Liability The Company generally provides a one-year
Deferred Revenue		Deferred Revenue Deferred revenue consists of payments received in advance of revenue recognition primarily related to console service agreements. Revenue under these agreements is recognized over the related service period. Deferred revenue that will be recognized during the 12 months following the balance sheet date is recorded as deferred revenue, current and the remaining portion is recorded as deferred revenue, noncurrent on the accompanying balance sheets.
Redeemable Convertible Preferred Stock Warrant Liability	Redeemable Convertible Preferred Stock Warrant Liability The Company has accounted for its freestanding warrants to purchase shares of the Company’s redeemable convertible preferred stock as liabilities at fair value upon issuance primarily because the shares underlying the warrants contained contingent redemption features outside the control of the Company. The warrants were subject to re-measurement at additional paid-in capital,	Redeemable Convertible Preferred Stock Warrant Liability The Company has accounted for its freestanding warrants to purchase shares of the Company’s redeemable convertible preferred stock as liabilities at fair value upon issuance primarily because the shares underlying the warrants contain contingent redemption features outside the control of the Company. The warrants are subject to re-measurement at The carrying value of the warrants will continue to be adjusted until such time as these instruments are exercised, expire or convert into warrants to purchase shares of the Company’s common stock. At that time, the liabilities will be reclassified to additional paid-in capital, The Company estimated the fair value of these liabilities using the Black-Scholes option pricing model and assumptions that were based on the individual characteristics of the warrants on the valuation date, as well as assumptions for future financings, expected volatility, expected life, yield, and risk-free interest rate.
Defined Contribution Plan		Defined Contribution Plan The Company has a defined contribution retirement savings plan under Section 401(k) of the Internal Revenue Code. This plan allows eligible employees to defer a portion of their annual compensation on a pre-tax
Revenue	Revenue The Company’s revenue is generated primarily from the sale of its products and services. Product revenue consists primarily of sales of the Tablo console and related consumables, including Tablo cartridges, used in treatment delivery. Service and other revenue consists primarily of revenue generated from consoles service contracts and other revenue from shipping and handling charged to customers. The Company considers each product and each service contract to be a distinct performance obligation. Revenue is recognized when a performance obligation is satisfied, which occurs when control of the promised products or services is transferred to the customer in an amount that reflects the consideration the Company expects to receive in exchange for those products or services. Revenue from product sales is recognized at a point in time when management has determined that control has transferred to the customer, which is generally when legal title has transferred to the customer. Revenue from service contracts is recognized as the output of the service is transferred to the customer over time, typically evenly over the contract term. Revenue is recognized net of allowances for returns and any taxes collected from customers, which are subsequently remitted to governmental authorities. The Company’s contracts with customers often include promises to transfer multiple products and services to a customer. Determining whether products and services are considered distinct performance obligations that should be accounted for separately versus together may require significant judgment. Judgment is also required to determine the stand-alone selling price (SSP) for each distinct performance obligation. The Company uses an observable price to estimate SSP for items that are sold separately, including customer support agreements. In instances where SSP is not directly observable, such as when the Company does not sell the product or service separately, the Company determines the SSP using information that may include market conditions and other observable inputs. When stand-alone selling prices have not been established for products, the Company will utilize the residual method to allocate revenue. The Company may offer additional goods or services to customers at the inception of customer contracts at prices not at SSP. This is considered a material right and an additional performance obligation of the contract. SSP is assigned based on the estimated value of the material right. Costs associated with product sales include commissions. The Company applies the practical expedient to expense the commissions as incurred as the expected amortization period is one year or less. Commissions are recorded as sales and marketing expenses in the accompanying condensed statements of operations. Operating Lease Arrangements The Company enters into operating lease arrangements that contain both lease and non-lease non-lease non-lease Shipping and Handling Costs Shipping and handling charged to customers are recorded as revenue. Shipping and handling costs are expensed as incurred and are included in sales and marketing expenses.	Revenue The Company recognizes revenue in accordance with ASC Topic 606, Revenue from Contracts with Customers (1) Identify the contract(s) with a customer; (2) Identify the performance obligations in the contract; (3) Determine the transaction price; (4) Allocate the transaction price to the performance obligations in the contract; and (5) Recognize revenue when (or as) the entity satisfies a performance obligation. The Company’s revenue is generated primarily from the sale of its products and services. Product revenue consists primarily of sales of the Tablo console and related consumables, including the Tablo cartridge, used in treatment delivery. Service revenue consists primarily of revenue generated from consoles service contracts. The Company considers each product and each service contract to be a distinct performance obligation. Revenue is recognized when a performance obligation is satisfied, which occurs when control of the promised products or services is transferred to the customer in an amount that reflects the consideration the Company expects to receive in exchange for those products or services. Revenue from product sales is recognized at a point in time when management has determined that control has transferred to the customer, which is generally when legal title has transferred to the customer. Revenue from service contracts is recognized as the output of the service is transferred to the customer over time, typically evenly over the contract term. Revenue is recognized net of allowances for returns and any taxes collected from customers, which are subsequently remitted to governmental authorities. The Company’s contracts with customers often include promises to transfer multiple products and services to a customer. Determining whether products and services are considered distinct performance obligations that should be accounted for separately versus together may require significant judgment. Judgment is also required to determine the stand-alone selling price (“SSP”) for each distinct performance obligation. The Company uses an observable price to estimate SSP for items that are sold separately, including customer support agreements. In instances where SSP is not directly observable, such as when the Company does not sell the product or service separately, the Company determines the SSP using information that may include market conditions and other observable inputs. When stand-alone selling prices have not been established for products, the Company will utilize the residual method to allocate revenue. The Company may offer additional goods or services to customers at the inception of customer contracts at prices not at SSP. This is considered a material right and an additional performance obligation of the contract. SSP is assigned based on the estimated value of the material right. Costs associated with product sales include commissions. The Company applies the practical expedient to expense the commissions as incurred as the expected amortization period is one year or less. Commissions are recorded as sales and marketing expenses in the statements of operations. Operating Lease Arrangements From time to time, the Company enters into operating lease arrangements that contain both lease and non-lease non-lease non-lease Shipping and Handling Costs Shipping and handling charged to customers are recorded as revenue. Shipping and handling costs, including the associated personnel, are expensed as incurred and are included in sales and marketing expenses. Contract Balances The timing of revenue recognition may differ from the timing of invoicing to customers. The Company records an unbilled receivable when revenue is recognized prior to invoicing, or deferred revenue when revenue is recognized subsequent to invoicing. For multi-year service agreements, the Company generally invoices customers annually at the beginning of each annual coverage period.
Research and Development		Research and Development The Company expenses all research and development costs as incurred. These expenses include the costs of proprietary research and development efforts, quality engineering, clinical studies and trials and regulatory affairs. Costs include salaries, employee benefits, and other headcount-related costs, prototype development costs, contract and other outside service fees, depreciation expense and allocated costs including facilities and information technology.
Advertising Costs		Advertising Costs Advertising costs are expensed as incurred. For the years ended December 31, 2018 and 2019, advertising costs were not significant.
Stock-Based Compensation	Stock-Based Compensation The Company’s stock-based compensation relates to stock options with a service condition, stock options with performance and market-based vesting conditions, and stock purchase rights under the Company’s Employee Stock Purchase Plan (ESPP). Stock-based compensation for its stock-based awards is based on their grant date fair value. Service-based options initially granted to an optionee generally vest at a rate of 25% on the first anniversary of the original vesting date, with the balance vesting monthly over the remaining three years. Any subsequent follow-on For stock options with performance and market-based vesting conditions, stock-based compensation is recognized when the performance vesting condition is considered probable of being satisfied. Prior to the Company’s IPO in September 2020, the Company had not recognized any stock-based compensation as the satisfaction of the performance condition was not considered probable. Upon the closing of the IPO, the Company recorded a cumulative stock-based compensation using the accelerated attribution method as the performance condition was satisfied. Compensation related to these options is not reversed if the achievement of the market condition does not occur. The fair value of these stock options is estimated using the Monte Carlo approach.	Stock-Based Compensation The Company accounts for stock-based compensation arrangements with employees and non-employee non-employees non-employee Service-based options initially granted to an optionee generally vest at a rate of 25% on the first anniversary of the original grant date, with the balance vesting monthly over the remaining three years. Any subsequent follow-on For stock options with performance and market-based vesting conditions, stock-based compensation is recognized when a performance vesting condition is considered probable of being achieved. Once the performance vesting condition is considered probable of being achieved, compensation costs related to awards with a performance and market-based condition are recognized regardless of whether the market condition is ultimately satisfied using the accelerated attribution method. Compensation cost is not reversed if the achievement of the market condition does not occur. The fair value of these share-based payment awards is estimated using the Monte Carlo approach.
Income Taxes		Income Taxes The Company accounts for income taxes under the asset and liability method. Under this method, deferred tax assets and liabilities are determined based on differences between financial reporting and tax reporting bases of assets and liabilities and remeasured using enacted tax rates and laws that are expected to be in effect when the differences are expected to reverse. Realization of deferred tax assets is dependent upon future earnings, the timing and amount of which are uncertain. The Company utilizes a two-step The Company includes any penalties and interest expense related to income taxes as a component of other expense, net, as necessary.
Net Loss Per Share Attributable to Common Stockholders	Net Loss Per Share Attributable to Common Stockholders Basic net loss per share attributable to common stockholders is calculated by dividing the net loss attributable to common stockholders by the weighted-average number of shares of common stock outstanding for the period, without consideration for potential dilutive securities. Diluted net loss per share is computed by dividing the net loss attributable to common stockholders by the weighted-average number of common shares and common share equivalents of potentially dilutive securities outstanding for the period. For purposes of the diluted net loss per share calculation, redeemable convertible preferred stock, warrants and awards under the Company’s equity compensation plan are considered to be potentially dilutive securities. For periods in which the Company reports net losses, diluted net loss per share attributable to common stockholders is the same as basic net loss per share attributable to common stockholders because potentially dilutive shares of common stock are not assumed to have been issued if their effect is antidilutive. Therefore, basic and diluted net loss per share was the same for all periods presented.	Net Loss per Share Attributable to Common Stockholders Basic net loss per share attributable to common stockholders is calculated by dividing the net loss attributable to common stockholders by the weighted-average number of shares of common stock outstanding for the period, without consideration for potential dilutive securities. Diluted net loss per share is computed by dividing the net loss by the weighted-average number of common shares and common share equivalents of potentially dilutive securities outstanding for the period. For purposes of the diluted net loss per share calculation, redeemable convertible preferred stock, warrants and common stock options are considered to be potentially dilutive securities. As the Company was in a loss position for the years ended December 31, 2018 and 2019, basic net loss per share attributable to common stockholders is the same as diluted net loss per share attributable to common stockholders because the effects of potentially dilutive securities are antidilutive.
Recently Adopted Accounting Pronouncements and Recently Issued Accounting Pronouncements Not Yet Adopted	Recently Adopted Accounting Pronouncements In August 2018, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2018-13, Fair Value Measurement (Topic 820): Disclosure Framework—Changes to the Disclosure Requirements for Fair Value Measurement 2018-13). 2018-13 Recently Issued Accounting Pronouncements Not Yet Adopted In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments—Credit Losses (Topic 326) Measurement of Credit Losses on Financial Instruments 2016-13), available-for-sale available-for-sale 2016-13 2019-10, Financial Instruments—Credit Losses (Topic 326), Derivatives and Hedging (Topic 815) and Leases (Topic 842): Effective Dates ASU 2016-13 2016-13 2016-13	Recently Adopted Accounting Pronouncements In June 2018, the FASB issued ASU No. 2018-07, Compensation—Stock Compensation (Topic 718) Improvements to Nonemployee Share-Based Payment Accounting No. 2018-07). No. 2018-07 In November 2016, the FASB issued ASU No. 2016-18, Statement of Cash Flows, Restricted Cash (Topic 230) Recently Issued Accounting Pronouncements Not Yet Adopted In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments—Credit Losses (Topic 326) Measurement of Credit Losses on Financial Instruments No. 2016-13), available-for-sale available-for-sale 2016-13 No. 2019-10, Financial Instruments—Credit Losses (Topic 326), Derivatives and Hedging (Topic 815) and Leases (Topic 842): Effective Dates No. 2016-13 No. 2016-13 In August 2018, the FASB issued ASU No. 2018-13, Fair Value Measurement (Topic 820): Disclosure Framework—Changes to the Disclosure Requirements for Fair Value Measurement No. 2018-13), Fair Value Measurement 2018-13
Contract Liabilities-Deferred Revenue	Contract Liabilities—Deferred Revenue The timing of revenue recognition may differ from the timing of invoicing to customers. The Company records deferred revenue when revenue is recognized subsequent to invoicing. For multi-year service agreements, the Company generally invoices customers annually at the beginning of each annual coverage period. Deferred revenue that will be recognized during the 12 months following the balance sheet date is recorded as the current portion of deferred revenue and the remaining portion is recorded as noncurrent.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Accounting Policies [Abstract]
Schedule of Reconciliation of Cash, Cash Equivalents and Restricted Cash	The following table provides a reconciliation of cash, cash equivalents and restricted cash that sum to the total of the amounts shown in the accompanying condensed statements of cash flows (in thousands): September 30, 2020 2019 Cash and cash equivalents $ 311,327 $ 39,216 Restricted cash 33,311 743 Total cash, cash equivalents and restricted cash $ 344,638 $ 39,959	The following table provides a reconciliation of cash, cash equivalents and restricted cash reported within the balance sheets that sum to the total of the amounts shown in the statements of cash flows: December 31, 2018 2019 Cash and cash equivalents $ 33,264 $ 36,926 Restricted cash 151 743 $ 33,415 $ 37,669

Revenue and Deferred Revenue (T

Revenue and Deferred Revenue (Tables)	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Revenue from Contract with Customer [Abstract]
Summary of Revenue by Source	Revenue by source consisted of the following (in thousands): Nine Months Ended 2020 2019 Consoles $ 22,230 $ 6,248 Consumables 4,205 1,253 Total product revenue 26,435 7,501 Service and other revenue 6,253 492 Total revenue $ 32,688 $ 7,993	Revenue by source consisted of the following (in thousands): December 31, 2018 2019 Consoles $ 1,226 $ 12,187 Consumables 523 1,563 Total product revenue $ 1,749 $ 13,750 Service revenue 258 1,328 Total revenue $ 2,007 $ 15,078
Schedule of Contract Liabilities	The following table summarized the Company’s contract liabilities (in thousands): September 30, December 31, Deferred revenue, current $ 4,132 $ 883 Deferred revenue, noncurrent 566 134 Total Deferred revenue $ 4,698 $ 1,017	The following information summarizes the Company’s contract liabilities (in thousands): December 31, 2018 2019 Deferred revenue, current $ 269 $ 883 Deferred revenue, noncurrent $ 13 $ 134

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Summary of Financial Assets and Liabilities Measured at Fair Value On Recurring Basis by Level Within Fair Value Hierarchy	The following tables summarize the Company’s financial assets and liabilities measured at fair value on a recurring basis by level within the fair value hierarchy (in thousands): September 30, 2020 Valuation Hierarchy Amortized Costs Gross Unrealized Holding Gains Gross Unrealized Holding Losses Aggregate Fair Value Assets: Cash equivalents: Money market funds Level 1 $ 43,058 $ — $ — $ 43,058 Short-term investments: U.S. Treasury securities Level 1 24,992 1 — 24,993 Corporate debt Level 2 7,895 — — 7,895 Total assets $ 75,945 $ 1 $ — $ 75,946 December 31, 2019 Valuation Hierarchy Amortized Costs Gross Unrealized Holding Gains Gross Unrealized Holding Losses Aggregate Fair Value Assets: Cash equivalents: Money market funds Level 1 $ 29,761 $ — $ — $ 29,761 Commercial paper Level 2 2,299 — — 2,299 Short-term investments: Commercial paper Level 2 10,972 — — 10,972 Corporate debt Level 2 17,357 19 — 17,376 Asset-backed securities Level 2 4,801 3 — 4,804 Total assets $ 65,190 $ 22 $ — $ 65,212 Liabilities: Redeemable convertible preferred stock warrant liability Level 3 $ 4,285 $ — $ — $ 4,285 Total liabilities $ 4,285 $ — $ — $ 4,285	The following tables present the Company’s assets and liabilities that are measured at fair value on a recurring basis by level within the fair value hierarchy (in thousands): December 31, 2018 Valuation Amortized Gross Gross Aggregate Assets: Cash equivalents: Money market funds Level 1 $ 21,889 $ — $ — $ 21,889 Repurchase agreements Level 2 6,000 — — 6,000 Short-term investments: Government debt Level 1 13,981 — (1 ) 13,980 Commercial paper Level 2 44,263 — — 44,263 Corporate debt Level 2 30,852 — (36 ) 30,816 Asset-backed securities Level 2 20,482 — (23 ) 20,459 Total assets $ 137,467 $ $ (60 ) $ 137,407 Liabilities: Redeemable convertible preferred stock warrant liability Level 3 $ 8,085 $ — $ — $ 8,085 Total liabilities $ 8,085 $ — $ — $ 8,085 December 31, 2019 Valuation Amortized Gross Gross Aggregate Assets: Cash equivalents: Money market funds Level 1 $ 29,761 $ — $ — $ 29,761 Commercial paper Level 2 2,299 — — 2,299 Short-term investments: Commercial paper Level 2 10,972 — — 10,972 Corporate debt Level 2 17,357 19 — 17,376 Asset-backed securities Level 2 4,801 3 — 4,804 Total assets $ 65,190 $ 22 $ — $ 65,212 Liabilities: Redeemable convertible preferred stock warrant liability Level 3 $ 4,285 $ — $ — $ 4,285 Total liabilities $ 4,285 $ — $ — $ 4,285
Schedule of Change in Fair Value of Redeemable Convertible Preferred Stock Warrant Liability	The change in fair value of the redeemable convertible preferred stock warrant liability was as follows (in thousands): Balance at December 31, 2019 $ 4,285 Change in fair value 93 Conversion of Series A redeemable convertible preferred stock warrants to common stock warrants upon the closing of the IPO (1,252 ) Reclassified to additional paid-in (3,126 ) Balance at September 30, 2020 $ —	The change in fair value of the Company’s redeemable convertible preferred stock warrant liability was as follows (in thousands): Years Ended December 31, 2018 2019 Beginning balance $ 7,823 $ 8,085 Change in fair value of redeemable convertible preferred stock warrant liability 262 (3,800 ) Ending balance $ 8,085 $ 4,285

Balance Sheet Components (Table

Balance Sheet Components (Tables)	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of Inventories	Inventories consist of the following (in thousands): September 30, December 31, Raw materials $ 6,163 $ 1,143 Work in process 2,758 842 Finished goods 2,889 2,611 Total inventories $ 11,810 $ 4,596	Inventories consist of the following (in thousands): December 31, 2018 2019 Raw material $ 846 $ 1,143 Work-in-process 1,728 842 Finished goods 448 2,611 $ 3,022 $ 4,596
Summary of Property Plant and Equipment		Property and equipment, net consist of the following (in thousands): December 31, 2018 2019 Computers and software $ 1,137 $ 1,857 Dialysis equipment 1,038 3,904 Machinery and equipment 991 761 Production tooling 871 2,782 Furniture and fixtures 487 1,087 Leasehold improvements 174 174 Total property and equipment 4,698 10,565 Less: Accumulated depreciation and amortization (2,223 ) (2,670 ) Property and equipment, net $ 2,475 $ 7,895
Accrued Expenses and Other Current Liabilities	Accrued expenses and other current liabilities consist of the following (in thousands): September 30, December 31, Accrued inventory $ 4,560 $ 798 Accrued research and development expenses 212 421 Accrued professional services 2,784 553 Others 1,403 1,137 Total accrued expenses and other current liabilities $ 8,959 $ 2,909	Accrued expenses and other current liabilities consist of the following (in thousands): December 31, 2018 2019 Accrued inventory $ 299 $ 798 Accrued research and development expenses 236 421 Accrued professional services 179 553 Operating lease liabilities 505 — Other 1,222 1,137 $ 2,441 $ 2,909
Accrued Warranty Liability	The change in accrued warranty liability is presented in the following table (in thousands): September 30, December 31, Balance at the beginning of the period $ 1,702 $ 293 Additions charge to cost of product revenue 3,808 2,578 Consumption (2,252 ) (1,169 ) Balance at the end of the period $ 3,258 $ 1,702	The change in accrued warranty liability is presented in the following table (in thousands): Years Ended December 31, 2018 2019 Balance at beginning of the year $ 736 $ 293 Provision for warranty liability made during the year 341 2,578 Consumption during the year (784 ) (1,169 ) Balance at end of the year $ 293 $ 1,702
Schedule of Other Assets	Other assets consist of the following (in thousands): September 30, December 31, Prepaid insurance, noncurrent $ 1,878 $ — Deposits 99 82 Total other assets $ 1,977 $ 82

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2019
Leases [Abstract]
Summary of Company ROU Assets and Lease Liabilities	The following table presents the Company’s ROU assets and lease liabilities (in thousands): December 31, Lease Classification Classification 2018 2019 Assets: Operating Current assets $ 451 $ — Financing Property and equipment 19 6 Total ROU assets $ 470 $ 6 Liabilities: Current: Operating Accrued expenses and other current liabilities $ 505 $ — Financing Accrued expenses and other current liabilities 10 9 Noncurrent: Operating Operating lease liability — — Financing Long-term debt 9 — Total lease liabilities $ 524 $ 9
Summary of Minimum Lease Payments of Lease Liabilities	As of December 31, 2019, the minimum lease payments of the Company’s lease liabilities are as follows (in thousands): Finance Year Ending December 31: 2020 $ 9 Total lease payments $ 9 Less: imputed interest — Total lease liabilities $ 9
Summary of Supplemental Cash Flows Information	The following information represents supplemental disclosure for the statements of cash flows related to the Company’s lease (in thousands): Years Ended December 31, 2018 2019 Supplemental Cash Flows Information: Cash paid for amounts included in the measurement of lease liabilities: Cash used in operating activities: Operating leases $ 464 $ 505 Financing leases $ 1 $ 1 Cash used in financing activities: Financing leases $ 9 $ 9

Term Loan (Tables)

Term Loan (Tables)	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Debt Disclosure [Abstract]
Schedule of Term Loan	Term loan consist of the following (in thousands): September 30, December 31, Principal of term loan $ 30,000 $ 30,000 Unamortized debt discount (348 ) (939 ) Total term loan 29,652 29,061 Less: term loan, current — (7,500 ) Term loan, noncurrent $ 29,652 $ 21,561	Term loans consist of the following (in thousands): December 31, 2018 2019 Principal of Perceptive term loan $ 30,000 $ 30,000 Unamortized discount (1,654 ) (939 ) Term loan, current and noncurrent 28,346 29,061 Less: term loan, current — (7,500 ) Term loan, noncurrent $ 28,346 $ 21,561
Summary of Debt Maturities		As of December 31, 2019, debt maturities for the next five years are as follows (in thousands): 2020 $ 7,500 2021 22,500 $ 30,000

Redeemable Convertible Prefer_3

Redeemable Convertible Preferred Stock and Stockholders' Deficit (Tables)	12 Months Ended
	Dec. 31, 2019
Equity [Abstract]
Summary of Redeemable Convertible Preferred Stock	Redeemable convertible preferred stock consists of the following (in thousands, except share and per share amounts): December 31, 2018 Shares Authorized Original Issue Shares Issued and Aggregate Carrying Series A 44,541,111 $ 1.0000 43,641,111 $ 74,493 $ 74,077 Series B 31,105,155 2.2674 28,929,196 87,580 87,276 Series C 32,946,219 2.5915 31,291,758 92,755 92,471 Series D 46,000,000 3.1100 43,352,179 138,719 138,460 154,592,485 147,214,244 $ 393,547 $ 392,284 December 31, 2019 Shares Authorized Original Issue Shares Issued and Aggregate Carrying Series A 44,541,111 $ 1.0000 43,641,111 $ 80,634 $ 77,503 Series B 31,105,155 2.2674 28,929,196 94,800 91,118 Series C 32,946,219 2.5915 31,291,758 100,401 96,502 Series D 46,000,000 3.1100 43,352,179 150,153 144,323 154,592,485 147,214,244 $ 425,988 $ 409,446
Summary of Reserved Shares of Common Stock on Converted Basis for Issuance	The Company has reserved shares of common stock, on an as-if December 31, 2018 2019 Redeemable convertible preferred stock 18,634,636 18,643,769 Warrants to purchase redeemable convertible preferred stock 598,785 504,791 Warrants to purchase common stock 8,860 — Options issued and outstanding 3,310,990 3,757,457 Options available for grant under stock option plan 639,442 195,439 23,192,713 23,101,456

Redeemable Convertible Prefer_4

Redeemable Convertible Preferred Stock Warrants and Common Stock Warrants (Tables)	12 Months Ended
	Dec. 31, 2019
Equity [Abstract]
Summary of Outstanding Warrants to Purchase Redeemable Convertible Preferred Stock	The key terms of the outstanding warrants to purchase redeemable convertible preferred stock are summarized in the following table: December 31, Class of Stock Exercise Grant Date Expiration Date 2018 2019 Series A redeemable convertible preferred stock $ 1.0000 July 2012 July 2019 400,000 — Series A redeemable convertible preferred stock 1.0000 September 2013 September 2023 1) 300,000 300,000 Series A redeemable convertible preferred stock 1.0000 September 2014 September 2024 1) 200,000 200,000 Series B redeemable convertible preferred stock 2.2674 September 2015 September 2025 2,109,804 2,109,804 Series B redeemable convertible preferred stock 2.2674 June 2016 June 2026 66,155 66,155 Series C redeemable convertible preferred stock 2.5915 June 2017 June 2027 1,654,461 1,654,461 4,730,420 4,330,420 1) The redeemable convertible preferred stock warrants expire at the later of the expiration date, or five years after an initial public offering by the Company.
Estimated Fair Value for Each Issuance of the Company's Warrants to Purchase Redeemable Convertible Preferred Stock	The following table sets forth the estimated fair value for each issuance of the Company’s warrants to purchase redeemable convertible preferred stock as of December 31, 2018 and 2019 (in thousands): December 31, Class of Warrants 2018 2019 2013 warrant to purchase Series A redeemable convertible preferred stock $ 397 $ 157 2014 warrant to purchase Series A redeemable convertible preferred stock 275 121 2015 warrant to purchase Series B redeemable convertible preferred stock 3,879 1,879 2016 warrant to purchase Series B redeemable convertible preferred stock 129 64 2017 warrant to purchase Series C redeemable convertible preferred stock 3,405 2,064 $ 8,085 $ 4,285
Warrants to Purchase Redeemable Convertible Preferred Stock Valued Using the Black-Scholes Option-pricing Model	The warrants to purchase redeemable convertible preferred stock were valued using the Black-Scholes option-pricing model at the issuance date and remeasured using the following assumptions: Years Ended December 31, 2018 2019 Market value of shares of redeemable convertible preferred stock $2.05 - $3.25 $1.36 - $2.40 Expected term (in years) 4.74 - 8.50 3.74 - 7.50 Expected volatility 48.8% - 50.1% 48.1% - 50.0% Risk-free interest rate 2.51% - 2.59% 1.76% - 1.83% Dividend yield 0% 0%

Stock-based Compensation (Table

Stock-based Compensation (Tables)	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Share-based Payment Arrangement [Abstract]
Summary of Stock Option Plan Activity		Stock option activity under the 2010 Plan was as follows: Options Available Number of Weighted Weighted Aggregate Balance as of December 31, 2018 639,442 3,310,990 $ 3.36 8.16 $ 2,490 Additional shares authorized 126,582 — Granted (937,484 ) 937,484 $ 5.62 Exercised — (124,118 ) $ 2.92 Cancelled and forfeited 366,899 (366,899 ) $ 3.24 Balance as of December 31, 2019 195,439 3,757,457 $ 3.95 7.81 $ 8,618 Vested and expected to vest as of December 31, 2019 3,603,449 $ 3.95 7.76 $ 8,396 Exercisable as of December 31, 2019 1,361,219 $ 1.34 6.16 $ 4,697
Summary of Ranges of Assumptions Used to Value Options with Service-Based and Performance Vesting Granted to Employees		The following ranges of assumptions were used to value options with service-based and/or performance vesting granted to employees: Years Ended December 31, 2018 2019 Expected term (in years) 4.78 - 4.98 4.97 - 5.05 Expected volatility 48.4% - 48.8% 49.3% - 50.9% Risk-free interest rate 2.65% - 3.02% 1.57% - 2.48% Dividend yield 0% 0%
Summary of Stock-based Compensation	The following table sets forth stock-based compensation included in the accompanying condensed statements of operations (in thousands): Nine Months Ended 2020 2019 Cost of revenue $ 181 $ 3 Research and development 3,326 266 Sales and marketing 2,828 119 General and administrative 8,836 248 Total stock-based compensation expense 15,171 636	The following table sets forth stock-based compensation included in the Company’s statements of operations (in thousands): Years Ended December 31, 2018 2019 Cost of revenue $ 14 $ 5 Research and development 234 227 Sales and marketing 176 189 General and administrative 364 462 Total stock-based compensation $ 788 $ 883

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Summary of Effective Tax Rate of the Provision for Income Taxes	The effective tax rate of the provision for income taxes differs from the federal statutory rate as follows: Years Ended December 31, 2018 2019 Federal statutory income tax rate 21.0 % 21.0 % State taxes 4.9 7.8 Change in valuation allowance (27.2 ) (28.5 ) Federal and state tax credits 2.0 0.9 Other (0.7 ) (1.2 ) — % — %
Summary of Components of the Deferred Tax Assets and Liabilities	The components of the deferred tax assets and liabilities are as follows (in thousands): December 31, 2018 2019 Deferred tax assets: Net operating loss carryforwards $ 43,405 $ 56,127 Tax credits 6,993 8,777 Accrual and reserves 1,126 1,675 Tangible and intangible assets 7,117 15,888 Stock-based compensation 551 733 Gross deferred tax assets 59,192 82,865 Valuation allowance (59,192 ) (82,865 ) Net deferred tax assets $ — $ — Deferred tax liabilities: Other intangibles $ — $ — Net deferred tax $ — $ —
Summary of Reconciliation of the Total Unrecognized Tax Benefits	A reconciliation of the total unrecognized tax benefits for the year ended December 31, 2019 is as follows (in thousands): Balance, beginning of year $ 8,385 Decrease related to current year positions (7,601 ) Increase related to current year positions 236 Balance, end of year $ 1,020

Net Loss per Share Attributab_2

Net Loss per Share Attributable to Common Stockholders (Tables)	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Earnings Per Share [Abstract]
Schedule of Outstanding Potentially Dilutive Shares were Excluded from Calculation of Diluted Net Loss Per Share	The following outstanding potentially dilutive shares were excluded from the calculation of diluted net loss per share due to their anti-dilutive effect (in thousands): Nine Months Ended 2020 2019 Redeemable convertible preferred stock, on an as-if — 18,644 Options to purchase common stock 4,742 3,852 Warrants to purchase redeemable convertible preferred stock — 505 Warrant to purchase common stock 63 — Shares committed under ESPP 5 — Total 4,810 23,001	The following outstanding potentially dilutive shares have been excluded from the calculation of diluted net loss per share due to their anti-dilutive effect: Years Ended December 31, 2018 2019 Redeemable convertible preferred stock on an as-if 18,634,636 18,643,769 Options to purchase common stock 3,310,990 3,757,457 Warrants to purchase redeemable convertible preferred stock 598,785 504,791 Warrants to purchase common stock 8,860 — Total 22,553,271 22,906,017
Schedule of Reconciliation of Numerator and Denominator Used in Calculation of Basic and Diluted Net Loss Per Share Attributable to Common Stockholders	A reconciliation of the numerator and denominator used in the calculation of basic and diluted net loss per share attributable to common stockholders is as follows (in thousands except per share amounts): Nine Months Ended 2020 2019 Numerator: Net loss $ (89,449 ) $ (48,853 ) Adjustment to redemption value on redeemable convertible preferred stock (362 ) (134,760 ) Deemed dividend on settlement of accrued dividend 42,530 — Gain on extinguishment of redeemable convertible preferred stock — 117,598 Net loss attributable to common stockholders, basic and diluted $ (47,281 ) $ (66,015 ) Denominator: Weighted-average shares of common stock, basic and diluted 7,508 838 Net loss per share attributable to common stockholders, basic and diluted $ (6.30 ) $ (78.77 )

Organization and Description _2

Organization and Description of Business - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended		12 Months Ended
	Mar. 31, 2020	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019	Dec. 31, 2018
Description of Business [Line Items]
Net loss		$ (89,449)	$ (48,853)	$ (68,299)	$ (49,780)
Accumulated deficit		(462,016)		(372,567)	(287,891)
Cash, cash equivalents and short-term investments		344,200		70,100
Restricted cash		33,311	$ 743	743	151
Cash, cash equivalents, restricted cash and short-term investments		377,500		$ 70,800
Gross proceeds redeemable convertible preferred stock		$ 126,758			$ 134,567
Series E Preferred Stock [Member]
Description of Business [Line Items]
Gross proceeds redeemable convertible preferred stock	$ 127,100

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Additional Information (Detail)	9 Months Ended		12 Months Ended
	Sep. 30, 2020USD ($)	Sep. 30, 2019USD ($)	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Summary Of Significant Accounting Policies [Line Items]
Restricted cash	$ 33,311,000	$ 743,000	$ 743,000	$ 151,000
Allowance for doubtful accounts	$ 29,000	$ 267,000	59,000
Inventory write-down			300,000	500,000
Impairment losses			$ 0	0
Capitalized contract cost amortization period description	The Company applies the practical expedient to expense the commissions as incurred as the expected amortization period is one year or less.		The Company applies the practical expedient to expense the commissions as incurred as the expected amortization period is one year or less.
Service-based options vesting period	3 years		3 years
General vesting period	4 years		4 years
Change in accounting principle, accounting standards update, adopted	true		true
Change in accounting principle, accounting standards update, adoption date	Jan. 1, 2020		Jan. 1, 2019
Change in accounting principle, accounting standards update, immaterial effect	false		false
Accounting Standards Update [Extensible List]	us-gaap:AccountingStandardsUpdate201813Member		us-gaap:AccountingStandardsUpdate201807Member
Other Assets
Summary Of Significant Accounting Policies [Line Items]
Unamortized deferred loan commitment costs			$ 0	$ 100,000
Customer Concentration Risk | Revenue Benchmark
Summary Of Significant Accounting Policies [Line Items]
Number of major customers			1	4
Customer Concentration Risk | Revenue Benchmark | Customer 1
Summary Of Significant Accounting Policies [Line Items]
Concentration of risk, percentage			11.00%	20.00%
Customer Concentration Risk | Revenue Benchmark | Customer 2
Summary Of Significant Accounting Policies [Line Items]
Concentration of risk, percentage				18.00%
Customer Concentration Risk | Revenue Benchmark | Customer 3
Summary Of Significant Accounting Policies [Line Items]
Concentration of risk, percentage				14.00%
Customer Concentration Risk | Revenue Benchmark | Customer 4
Summary Of Significant Accounting Policies [Line Items]
Concentration of risk, percentage				12.00%
Customer Concentration Risk | Accounts Receivable
Summary Of Significant Accounting Policies [Line Items]
Number of major customers			4	4
Allowance for doubtful accounts			$ 59,000
Customer Concentration Risk | Accounts Receivable | Customer 1
Summary Of Significant Accounting Policies [Line Items]
Concentration of risk, percentage			22.00%	28.00%
Customer Concentration Risk | Accounts Receivable | Customer 2
Summary Of Significant Accounting Policies [Line Items]
Concentration of risk, percentage			13.00%	24.00%
Customer Concentration Risk | Accounts Receivable | Customer 3
Summary Of Significant Accounting Policies [Line Items]
Concentration of risk, percentage			11.00%	16.00%
Customer Concentration Risk | Accounts Receivable | Customer 4
Summary Of Significant Accounting Policies [Line Items]
Concentration of risk, percentage			10.00%	12.00%
First Anniversary
Summary Of Significant Accounting Policies [Line Items]
Vesting rate	25.00%		25.00%

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Schedule of Reconciliation of Cash, Cash Equivalents and Restricted Cash (Detail) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019	Sep. 30, 2019	Dec. 31, 2018
Accounting Policies [Abstract]
Cash and cash equivalents	$ 311,327	$ 36,926	$ 39,216	$ 33,264
Restricted cash	33,311	743	743	151
Total cash, cash equivalents and restricted cash	$ 344,638	$ 37,669	$ 39,959	$ 33,415

Revenue and Deferred Revenue -

Revenue and Deferred Revenue - Summary of Revenue by Source (Detail) - USD ($) $ in Thousands	9 Months Ended		12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019	Dec. 31, 2018
Disaggregation of Revenue [Line Items]
Revenue	$ 32,688	$ 7,993	$ 15,078	$ 2,007
Consoles Product
Disaggregation of Revenue [Line Items]
Revenue	22,230	6,248	12,187	1,226
Consumables Product
Disaggregation of Revenue [Line Items]
Revenue	4,205	1,253	1,563	523
Product Revenue
Disaggregation of Revenue [Line Items]
Revenue	26,435	7,501	13,750	1,749
Service and Other Revenue
Disaggregation of Revenue [Line Items]
Revenue	$ 6,253	$ 492	$ 1,328	$ 258

Revenue and Deferred Revenue _2

Revenue and Deferred Revenue - Additional Information (Detail) - USD ($) $ in Millions	9 Months Ended		12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019	Dec. 31, 2018
Deferred revenue	$ 4.7		$ 1
Revenue recognized	$ 0.8		0.3	$ 0.3
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01
Revenue, Remaining Performance Obligation, Amount			0.9
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-10-01
Revenue, Remaining Performance Obligation, Amount		$ 4.1
Remaining performance obligations			$ 0.1
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period		12 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-10-01
Remaining performance obligations		$ 0.6
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period		12 months

Revenue and Deferred Revenue _3

Revenue and Deferred Revenue - Schedule of Contract liabilities (Detail) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenue from Contract with Customer [Abstract]
Deferred revenue, current	$ 4,132	$ 883	$ 269
Deferred revenue, noncurrent	566	134	$ 13
Total Deferred revenue	$ 4,698	$ 1,017

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Financial Assets and Liabilities Measured at Fair Value On Recurring Basis by Level Within Fair Value Hierarchy (Detail) - Fair Value, Recurring - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Sep. 30, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized Costs	$ 65,190	$ 137,467	$ 75,945
Gross Unrealized Holding Gains	22		1
Gross Unrealized Holding Loss		(60)
Aggregate Fair Value	65,212	137,407	75,946
Amortized Costs	4,285	8,085
Aggregate Fair Value	4,285	8,085
Level 1 | Cash equivalents | Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized Costs	29,761	21,889	43,058
Aggregate Fair Value	29,761	21,889	43,058
Level 1 | Short-term investments | US Government Agencies Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized Costs		13,981
Gross Unrealized Holding Loss		(1)
Aggregate Fair Value		13,980
Level 2 | Cash equivalents | Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized Costs	2,299
Aggregate Fair Value	2,299
Level 2 | Cash equivalents | Repurchase agreements
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized Costs		6,000
Aggregate Fair Value		6,000
Level 2 | Short-term investments | U.S. Treasury securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized Costs			24,992
Gross Unrealized Holding Gains			1
Aggregate Fair Value			24,993
Level 2 | Short-term investments | Corporate debt
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized Costs	17,357	30,852	7,895
Gross Unrealized Holding Gains	19
Gross Unrealized Holding Loss		(36)
Aggregate Fair Value	17,376	30,816	$ 7,895
Level 2 | Short-term investments | Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized Costs	10,972	44,263
Aggregate Fair Value	10,972	44,263
Level 2 | Short-term investments | Asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized Costs	4,801	20,482
Gross Unrealized Holding Gains	3
Gross Unrealized Holding Loss		(23)
Aggregate Fair Value	4,804	20,459
Level 3 | Redeemable convertible preferred stock warrant liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized Costs	4,285	8,085
Aggregate Fair Value	$ 4,285	$ 8,085

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Sep. 30, 2020	Sep. 15, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Transfer between levels	$ 0	$ 0
Maturity terms	1 year
Interest income	$ 2,500,000	$ 1,800,000
Available-for-sale securities in unrealized loss position	$ 0		$ 0
IPO
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Share price				$ 27
IPO | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Share price				$ 27

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Change in Fair Value of Redeemable Convertible Preferred Stock Warrant Liability (Detail) - Level 3 - Redeemable convertible preferred stock warrant liability - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019	Dec. 31, 2018
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance	$ 4,285	$ 8,085	$ 7,823
Change in fair value	93	(3,800)	262
Conversion of Series A redeemable convertible preferred stock warrants to common stock warrants upon the closing of the IPO	(1,252)
Reclassified to additional paid-in capital	$ (3,126)
Ending balance		$ 4,285	$ 8,085

Balance Sheet Components - Sche

Balance Sheet Components - Schedule of Inventories (Detail) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019	Dec. 31, 2018
Inventory Disclosure [Abstract]
Raw materials	$ 6,163	$ 1,143	$ 846
Work in process	2,758	842	1,728
Finished goods	2,889	2,611	448
Total inventories	$ 11,810	$ 4,596	$ 3,022

Balance Sheet Components - Summ

Balance Sheet Components - Summary of Property Plant and Equipment (Detail) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Total property and equipment		$ 10,565	$ 4,698
Less: Accumulated depreciation and amortization		(2,670)	(2,223)
Property and equipment, net	$ 14,412	7,895	2,475
Computers and Software
Property, Plant and Equipment [Line Items]
Total property and equipment		1,857	1,137
Dialysis Equipment
Property, Plant and Equipment [Line Items]
Total property and equipment		3,904	1,038
Machinery and Equipment
Property, Plant and Equipment [Line Items]
Total property and equipment		761	991
Production Tooling
Property, Plant and Equipment [Line Items]
Total property and equipment		2,782	871
Furniture and Fixtures
Property, Plant and Equipment [Line Items]
Total property and equipment		1,087	487
Leasehold Improvements
Property, Plant and Equipment [Line Items]
Total property and equipment		$ 174	$ 174

Balance Sheet Components - Addi

Balance Sheet Components - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Abstract]
Total depreciation and amortization expense	$ 1.5	$ 1.1

Balance Sheet Components - Accr

Balance Sheet Components - Accrued Expenses and Other Current Liabilities (Detail) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019	Dec. 31, 2018
Payables and Accruals [Abstract]
Accrued inventory	$ 4,560	$ 798	$ 299
Accrued research and development expenses	212	421	236
Accrued professional services	2,784	553	179
Operating lease liabilities	782		505
Others	1,403	1,137	1,222
Total accrued expenses and other current liabilities	$ 8,959	$ 2,909	$ 2,441

Balance Sheet Components - Ac_2

Balance Sheet Components - Accrued Warranty Liability (Detail) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019	Dec. 31, 2018
Product Warranties Disclosures [Abstract]
Balance at the beginning of the period	$ 1,702	$ 293	$ 736
Additions charge to cost of product revenue	3,808	2,578	341
Consumption	(2,252)	(1,169)	(784)
Balance at the end of the period	$ 3,258	$ 1,702	$ 293

Leases - Additional Information

Leases - Additional Information (Detail) - USD ($) $ in Thousands	1 Months Ended
	Sep. 30, 2019	Dec. 31, 2019	Dec. 31, 2018
Lessee, Lease, Description [Line Items]
Tenant improvement allowance	$ 2,000
Operating Leases, Total minimum lease payments	8,800
Operating lease cost	$ 600
Principal payment realated to finance lease		$ 9,000	$ 8,000
Weighted average remaining lease term, Finance leases		6 months
Weighted average discount rate, Finance leases		10.60%
Standby Letters of Credit
Lessee, Lease, Description [Line Items]
Letter of credit issued in lieu of a cash security deposit		$ 200

Leases - Summary of Company ROU

Leases - Summary of Company ROU Assets and Lease Liabilities (Detail) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019	Dec. 31, 2018
Assets:
Operating Current assets	$ 8,498		$ 451
Financing Property and equipment		$ 6	19
Total ROU assets		6	470
Current:
Operating Accrued expenses and other current liabilities	782		505
Financing Accrued expenses and other current liabilities		9	10
Noncurrent:
Operating Operating lease liability	$ 8,309	0	0
Financing Long-term debt			9
Total lease liabilities		$ 9	$ 524

Leases - Summary of Minimum Lea

Leases - Summary of Minimum Lease Payments of Lease Liabilities (Detail) $ in Thousands	Dec. 31, 2019USD ($)
Year Ending December 31:
2020	$ 9
Total lease payments	9
Less: imputed interest	0
Total lease liabilities	$ 9

Leases - Summary of Supplementa

Leases - Summary of Supplemental Cash Flows Information (Detail) - USD ($) $ in Thousands	9 Months Ended		12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019	Dec. 31, 2018
Cash used in operating activities:
Operating leases			$ 505	$ 464
Financing leases			1	1
Cash used in financing activities:
Financing leases	$ 8	$ 6	$ 9	$ 9

Commitment and Contingencies -

Commitment and Contingencies - Additional Information (Detail) - Purchase Commitment $ in Millions	12 Months Ended
	Dec. 31, 2019USD ($)
Purchase commitments	$ 15.5
Purchase commitment descriptions	Payment within the next 12 months

Term Loan - Schedule of Term Lo

Term Loan - Schedule of Term Loan (Detail) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019	Dec. 31, 2018
Debt Disclosure [Abstract]
Principal of Perceptive term loan	$ 30,000	$ 30,000	$ 30,000
Unamortized debt discount	(348)	(939)	(1,654)
Term loan, current and noncurrent	29,652	29,061	28,346
Less: term loan, current		(7,500)
Term loan, noncurrent	$ 29,652	$ 21,561	$ 28,346

Term Loan - Additional Informat

Term Loan - Additional Information (Detail) - USD ($)	Jul. 02, 2020	Jun. 30, 2017	Jul. 31, 2020	Sep. 30, 2020	Dec. 31, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Principal of term loan				$ 30,000,000	$ 30,000,000	$ 30,000,000
Outstanding principal balance				29,652,000	$ 29,061,000	$ 28,346,000
Warrants issued					4,330,420	4,730,420
Debt discount on Perceptive Term Loan				348,000	$ 939,000	$ 1,654,000
Deferred loan commitment cost					200,000
Debt financing costs on issuance					700,000
Debt discount on the Perceptive Term Loan					500,000
Final payment fee					$ 300,000
Final payment fee, percentage					1.10%
Term Loan B remaining borrowing amount					$ 10,000,000
Early payment fee as percentage of Outstanding principal balance						6.00%
Annual decrease in early payment fee as percentage of Outstanding principal balance					1.00%
Early prepayment fee, amount					$ 900,000
Loss on extinguishment of term loan				$ 1,567,000
Minimum
Debt Instrument [Line Items]
Early payment fee as percentage of Outstanding principal balance					3.00%
Perceptive Term Loan
Debt Instrument [Line Items]
Credit facility, maximum borrowing capacity		$ 40,000,000
Debt interest rate		8.55%			10.65%
Description of variable rate basis				Three-month LIBOR	Three-month LIBOR
Basis spread on variable rate		2.00%
Principal of term loan		$ 30,000,000
Outstanding principal balance		29,500,000
term loan upfront fee		$ 300,000
Warrants issued					1,654,461
Warrants exercise price					$ 2.5915
Total warrants issued					1,240,846
Allocation of warrants					413,615
Fair value of warrant on issuance					$ 3,000,000
Debt discount on Perceptive Term Loan					2,200,000
Deferred loan commitment cost					800,000
Periodic principal payment					$ 3,800,000
Loan maturity date		Jun. 30, 2017			Jun. 30, 2021
Net cash proceeds as a result of mandatory loan prepayment					$ 300,000
Description of payment terms					(i) 100% of the net cash proceeds received by the Company, (ii) the applicable prepayment premium on the principal amount of the Perceptive Term Loans being so prepaid, (iii) any accrued but unpaid interest on such principal amount of the Perceptive Term Loans being so prepaid less, subject to certain conditions, (iv) costs to acquire or repair fixed or capital assets useful in the business.
Early prepayment, accrued interest and exit fees			$ 1,200,000
SVB Term Loan
Debt Instrument [Line Items]
Debt interest rate	6.75%			3.75%
Principal of term loan	$ 30,000,000
Debt discount on Perceptive Term Loan				$ 300,000
Loan maturity date	Nov. 1, 2025
Description of payment terms				Payments under the SVB Term Loan are for interest only through May 2023, and then 30 monthly principal and interest from June 2023 until maturity.
Debt instrument interest only payments end date	2023-05
Debt instrument principal repayment period	30 months
Debt instrument, final payment amount	$ 2,000,000
Percentage of limitation on pledges of capital stock of foreign subsidiaries	65.00%
Other debt issuance costs				$ 400,000
SVB Term Loan | Minimum
Debt Instrument [Line Items]
Debt instrument prepayment fee percentage	1.00%
SVB Term Loan | Maximum
Debt Instrument [Line Items]
Debt instrument prepayment fee percentage	3.00%
SVB Term Loan | Prime Rate
Debt Instrument [Line Items]
Basis spread on variable rate	0.50%

Term Loan - Summary of Debt Mat

Term Loan - Summary of Debt Maturities (Detail) $ in Thousands	Dec. 31, 2019USD ($)
Debt Disclosure [Abstract]
2020	$ 7,500
2021	22,500
Debt, total	$ 30,000

Redeemable Convertible Prefer_5

Redeemable Convertible Preferred Stock and Stockholders' Deficit - Additional Information (Detail) $ / shares in Units, $ in Thousands	Sep. 17, 2019USD ($)$ / shares	Nov. 30, 2018USD ($)$ / sharesshares	Aug. 31, 2018USD ($)$ / sharesshares	Sep. 30, 2020USD ($)$ / sharesshares	Dec. 31, 2019USD ($)Installment$ / shares	Dec. 31, 2018USD ($)$ / sharesshares
Proceed from issuance of redeemable convertible preferred stock | $				$ 126,758		$ 134,567
Minimum mandatory conversion of accrued dividends proceeds | $	$ 50,000
Recognized gain on extinguishment redeemable convertible preferred stock | $	117,600
Difference between net carrying value outstanding redeemable convertible preferred stock | $	415,100
Fair value of redeemable convertible preferred stock | $	297,500
Issuance costs of redeemable convertible preferred stock | $	$ 200
Expected term (in years)	2 years
Expected volatility	57.10%
Risk-free interest rate	1.72%
Accrued Dividends | $					$ 74,800
Proceeds before reduction for the underwriting discount, commissions and expenses | $					$ 40,000
Offering price per share					$ 17.30
Redemption rights					Prior to the Amendment, the redemption value was for cash at a price equal to the original issue price, less the per share amount repaid, plus any dividends accrued, but unpaid, whether or not declared, together with any other dividends declared but unpaid in three equal annual installments starting with the first payment no later than thirty days following the receipt by the Company a Redemption Request.
Number of installments | Installment					3
Payment period					30 days
Series A Preferred Stock | Minimum
Preferred stock conversion prices	$ 7.9000
Series A Preferred Stock | Maximum
Preferred stock conversion prices	10.5331
Series B Preferred Stock | Minimum
Preferred stock conversion prices	17.9125
Series B Preferred Stock | Maximum
Preferred stock conversion prices	19.9025
Series C Preferred Stock | Minimum
Preferred stock conversion prices	20.4729
Series C Preferred Stock | Maximum
Preferred stock conversion prices	20.4729
Series D Preferred Stock | Minimum
Preferred stock conversion prices	24.5690
Series D Preferred Stock | Maximum
Preferred stock conversion prices	18.6124
Redeemable Convertible Preferred Stock
Issuance of Series D redeemable convertible preferred stock,(shares) | shares				57,782,000		43,352,179
Issuance of Series D redeemable convertible preferred stock, per share				$ 0.001	$ 0.001	$ 0.001
Divident rate					8.00%
Net cash proceeds | $					$ 50,000
Percentage of shares outstanding					66.66%
Accrued Dividends | $					$ 84,300	$ 68,400
Voting Rights					The holders of the majority of the outstanding shares of Series A redeemable convertible preferred stock, exclusively and as a separate class, shall be entitled to elect a majority of the directors of the Company, and the holders of the majority of the outstanding shares of Series D redeemable convertible preferred stock, exclusively and as a separate class, shall be entitled to elect one director of the Company.
Redeemable Convertible Preferred Stock | Minimum
Expected term (in years)					3 years 8 months 26 days	4 years 8 months 26 days
Expected volatility					48.10%	48.80%
Risk-free interest rate					1.76%	2.51%
Redeemable Convertible Preferred Stock | Maximum
Expected term (in years)					7 years 6 months	8 years 6 months
Expected volatility					50.00%	50.10%
Risk-free interest rate					1.83%	2.59%
Series D Redeemable Convertible Preferred Stock
Issuance of Series D redeemable convertible preferred stock,(shares) | shares		43,352,179	43,352,179
Issuance of Series D redeemable convertible preferred stock, per share		$ 3.11	$ 3.11
Proceed from issuance of redeemable convertible preferred stock | $		$ 134,600	$ 134,600
Accrued Dividends | $					$ 9,500
Conversion price	24.5690				$ 18.6124
Adjusted conversion price					0.1671
Conversion of preferred stock into common stock shares					$ 0.1671
Liquidation preference	3.11
Redemption rights					Prior to the Amendment, the redemption value was for cash at a price equal to the original issue price, less the per share amount repaid, plus any dividends accrued, but unpaid, whether or not declared, together with any other dividends declared but unpaid in three equal annual installments starting with the first payment no later than thirty days following the receipt by the Company a Series D Redemption Request.
Series A Redeemable Convertible Preferred Stock
Conversion price	7.9000				$ 10.5331
Adjusted conversion price					0.0949
Conversion of preferred stock into common stock shares					0.0949
Liquidation preference	1
Series B Redeemable Convertible Preferred Stock
Conversion price	17.9125				19.9025
Adjusted conversion price					0.1139
Conversion of preferred stock into common stock shares					0.1139
Liquidation preference	2.2674
Series C Redeemable Convertible Preferred Stock
Conversion price	20.4729				20.4729
Adjusted conversion price					0.1266
Conversion of preferred stock into common stock shares					$ 0.1266
Liquidation preference	$ 2.5915

Redeemable Convertible Prefer_6

Redeemable Convertible Preferred Stock and Stockholders' Deficit - Summary of Redeemable Convertible Preferred Stock (Detail) - USD ($) $ / shares in Units, $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Shares Authorized	154,592,485	154,592,485
Shares Issued and Outstanding	147,214,244	147,214,244
Aggregate Liquidation Amount	$ 425,988	$ 393,547
Carrying Value	$ 409,446	$ 392,284
Series A Redeemable Convertible Preferred Stock
Shares Authorized	44,541,111	44,541,111
Original Issue Price	$ 1	$ 1
Shares Issued and Outstanding	43,641,111	43,641,111
Aggregate Liquidation Amount	$ 80,634	$ 74,493
Carrying Value	$ 77,503	$ 74,077
Series B Redeemable Convertible Preferred Stock
Shares Authorized	31,105,155	31,105,155
Original Issue Price	$ 2.2674	$ 2.2674
Shares Issued and Outstanding	28,929,196	28,929,196
Aggregate Liquidation Amount	$ 94,800	$ 87,580
Carrying Value	$ 91,118	$ 87,276
Series C Redeemable Convertible Preferred Stock
Shares Authorized	32,946,219	32,946,219
Original Issue Price	$ 2.5915	$ 2.5915
Shares Issued and Outstanding	31,291,758	31,291,758
Aggregate Liquidation Amount	$ 100,401	$ 92,755
Carrying Value	$ 96,502	$ 92,471
Series D Redeemable Convertible Preferred Stock
Shares Authorized	46,000,000	46,000,000
Original Issue Price	$ 3.1100	$ 3.1100
Shares Issued and Outstanding	43,352,179	43,352,179
Aggregate Liquidation Amount	$ 150,153	$ 138,719
Carrying Value	$ 144,323	$ 138,460

Redeemable Convertible Prefer_7

Redeemable Convertible Preferred Stock and Stockholders' Deficit - Summary of Reserved Shares of Common Stock on Converted Basis for Issuance (Detail) - shares	Dec. 31, 2019	Dec. 31, 2018
Reserved shares of common stock	23,101,456	23,192,713
Options Issued and Outstanding
Reserved shares of common stock	3,757,457	3,310,990
Options Available for Grant Under Stock Option Plan
Reserved shares of common stock	195,439	639,442
Redeemable Convertible Preferred Stock
Reserved shares of common stock	18,643,769	18,634,636
Warrants to Purchase Redeemable Convertible Preferred Stock
Reserved shares of common stock	504,791	598,785
Warrant to Purchase Common Stock
Reserved shares of common stock		8,860

Redeemable Convertible Prefer_8

Redeemable Convertible Preferred Stock Warrants and Common Stock Warrants - Summary of Outstanding Warrants to Purchase Redeemable Convertible Preferred Stock (Detail) - $ / shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Warrant outstanding	4,330,420	4,730,420
Series A Redeemable Convertible Preferred Stock | July 2012
Exercise Price	$ 1
Warrant outstanding		400,000
Expiration Date	2019-07
Series A Redeemable Convertible Preferred Stock | September 2013
Exercise Price	$ 1
Warrant outstanding	300,000	300,000
Expiration Date	2023-09
Series A Redeemable Convertible Preferred Stock | September 2014
Exercise Price	$ 1
Warrant outstanding	200,000	200,000
Expiration Date	2024-09
Series B Redeemable Convertible Preferred Stock | September 2015
Exercise Price	$ 2.2674
Warrant outstanding	2,109,804	2,109,804
Expiration Date	2025-09
Series B Redeemable Convertible Preferred Stock | June 2016
Exercise Price	$ 2.2674
Warrant outstanding	66,155	66,155
Expiration Date	2026-06
Series C Redeemable Convertible Preferred Stock | June 2017
Exercise Price	$ 2.5915
Warrant outstanding	1,654,461	1,654,461
Expiration Date	2027-06

Redeemable Convertible Prefer_9

Redeemable Convertible Preferred Stock Warrants and Common Stock Warrants - Additional Information (Detail) - USD ($)	Sep. 15, 2020	Jul. 31, 2019	Sep. 30, 2020	Dec. 31, 2019
Class of Stock [Line Items]
Warrant to purchase shares				$ 8,860
Fair value				$ 30,000
Exercise price				$ 8.61
Preferred stock warrants outstanding	$ 0
Aggregate cash proceed of redeemable convertible preferred stock warrant			$ 4,288,000
Series A Redeemable Convertible Preferred Stock
Class of Stock [Line Items]
Warrant to purchase shares		400,000
Series A Redeemable Convertible Preferred Stock Warrants
Class of Stock [Line Items]
Number of redeemable convertible preferred stock warrants converted	500,000
Common stock warrants / Common stock issued upon conversion	63,000
Warrants exercise price	$ 7.96
Common stock warrants expiration date	2025-09
Series B Redeemable Convertible Preferred Stock Warrants
Class of Stock [Line Items]
Common stock warrants / Common stock issued upon conversion	65,000
Warrants exercise price	$ 2.2674
Number of redeemable convertible preferred stock warrants converted	2,176,000
Share price	$ 27
Series C Redeemable Convertible Preferred Stock Warrants
Class of Stock [Line Items]
Common stock warrants / Common stock issued upon conversion	209,000
Warrants exercise price	$ 2.5915
Number of redeemable convertible preferred stock warrants converted	1,655,000
Aggregate cash proceed of redeemable convertible preferred stock warrant	$ 4,300,000

Redeemable Convertible Prefe_10

Redeemable Convertible Preferred Stock Warrants and Common Stock Warrants - Estimated Fair Value for Each Issuance of the Company's Warrants to Purchase Redeemable Convertible Preferred Stock (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Issuance of the Company's warrants to purchase redeemable convertible preferred stock	$ 4,285	$ 8,085
2013 Warrant to Purchase Series A Redeemable Convertible Preferred Stock
Issuance of the Company's warrants to purchase redeemable convertible preferred stock	157	397
2014 Warrant to Purchase Series A Redeemable Convertible Preferred Stock
Issuance of the Company's warrants to purchase redeemable convertible preferred stock	121	275
2015 Warrant to Purchase Series A Redeemable Convertible Preferred Stock
Issuance of the Company's warrants to purchase redeemable convertible preferred stock	1,879	3,879
2016 Warrant to Purchase Series A Redeemable Convertible Preferred Stock
Issuance of the Company's warrants to purchase redeemable convertible preferred stock	64	129
2017 Warrant to Purchase Series A Redeemable Convertible Preferred Stock
Issuance of the Company's warrants to purchase redeemable convertible preferred stock	$ 2,064	$ 3,405

Redeemable Convertible Prefe_11

Redeemable Convertible Preferred Stock Warrants and Common Stock Warrants - Warrants to Purchase Redeemable Convertible Preferred Stock Valued Using the Black-Scholes Option-pricing Model (Detail)	Sep. 17, 2019	Dec. 31, 2019	Dec. 31, 2018
Expected term (in years)	2 years
Expected volatility	57.10%
Risk-free interest rate	1.72%
Redeemable Convertible Preferred Stock
Dividend yield		0.00%	0.00%
Minimum | Redeemable Convertible Preferred Stock
Expected term (in years)		3 years 8 months 26 days	4 years 8 months 26 days
Expected volatility		48.10%	48.80%
Risk-free interest rate		1.76%	2.51%
Minimum | Redeemable Convertible Preferred Stock | Measurement Input, Share Price
Market value of shares of redeemable convertible preferred stock		1.36	2.05
Maximum | Redeemable Convertible Preferred Stock
Expected term (in years)		7 years 6 months	8 years 6 months
Expected volatility		50.00%	50.10%
Risk-free interest rate		1.83%	2.59%
Maximum | Redeemable Convertible Preferred Stock | Measurement Input, Share Price
Market value of shares of redeemable convertible preferred stock		2.40	3.25

Equity Incentive Plan - Additio

Equity Incentive Plan - Additional Information (Detail) - USD ($) $ / shares in Units, shares in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total intrinsic value of options exercised	$ 200,000	$ 100,000
Number of coupons issued in effect at the time of grant	0
Dividend yield	0.00%	0.00%
Shares issued of stock options with performance and market-based conditions to employees	632,064	321,268
Associated expense was recognized	$ 0	$ 0
Unamortized deferred stock-based compensation relating to the performance and market-based conditions	$ 18,700,000
2010 Plan [Member]
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total shares authorized under 2010 plan	4,710,376
Unrecognized compensation cost related to stock-based compensation arrangements granted	$ 800,000
Expected cost recognized over a weighted average period	8 months 1 day
2019 Plan
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock Options Terms of Award	The 2019 Plan authorizes grants to purchase shares of authorized but unissued common stock. Stock options can be granted with an exercise price less than, equal to or greater than the stock's fair market value at the date of grant. All awards have 10-year terms. The Company currently uses authorized and unissued shares to satisfy share award exercises. The 2019 Plan permits incentive stock options, or ISOs and non-qualified stock options, or NSOs to be granted at prices no less than 100% of the estimated fair market value per share on the grant date. If the stock options are granted to a 10% stockholder, then the exercise price per share may not be less than 110% of the fair market value per share of the Company's common stock on the grant date.
Share-based Payment Arrangement, Employee
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Weighted average grant date fair value of options granted to employees	$ 2.77	$ 1.90
Total fair value of options vested	$ 700,000	$ 700,000

Equity Incentive Plan - Summary

Equity Incentive Plan - Summary of Stock Option Plan Activity (Detail) - 2010 Plan [Member] - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options available for grant, additional shares authorized	126,582
Options available for grant,granted	(937,484)
Options available for grant,cancelled and forfeited	366,899
Options available for grant balance as of December 31, 2018	195,439	639,442
Number of options, Granted	937,484
Number of options,Exercised	(124,118)
Number of options, Cancelled and forfeited	(366,899)
Number of options outstanding balance as of December 31, 2018	3,757,457	3,310,990
Vested and expected to vest as of December 31, 2019	3,603,449
Exercisable as of December 31, 2019	1,361,219
Weighted average exercise price, granted	$ 5.62
Weighted average exercise price, exercised	2.92
Weighted average exercise price,cancelled and forfeited	3.24
Weighted average exercise price balance as of December 31, 2018	3.95	$ 3.36
Weighted average exercise price vested and expected to vest as of December 31, 2019	3.95
Weighted average exercise price exercisable as of December 31, 2019	$ 1.34
Weighted average remaining contractual term	7 years 9 months 21 days	8 years 1 month 28 days
Weighted Average Remaining Contractual term, vested and expected to vest at end of period	7 years 9 months 3 days
Weighted Average Remaining Contractual term, exercisable at end of period	6 years 1 month 28 days
Aggregate intrinsic value	$ 8,618	$ 2,490
Aggregate intrinsic value, options vested and expected to vest-December 31, 2019	8,396
Aggregate intrinsic value, options exercisable-December 31, 2019	$ 4,697

Equity Incentive Plan - Summa_2

Equity Incentive Plan - Summary of Ranges of Assumptions Used to Value Options with Service-Based and Performance Vesting Granted to Employees (Detail)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Equity Incentive Plan [Line Items]
Dividend yield	0.00%	0.00%
Minimum
Equity Incentive Plan [Line Items]
Expected term (in years)	4 years 11 months 19 days	4 years 9 months 10 days
Expected volatility	49.30%	48.40%
Risk-free interest rate	1.57%	2.65%
Maximum
Equity Incentive Plan [Line Items]
Expected term (in years)	5 years 18 days	4 years 11 months 23 days
Expected volatility	50.90%	48.80%
Risk-free interest rate	2.48%	3.02%

Stock-based Compensation - Summ

Stock-based Compensation - Summary of Stock-based Compensation (Detail) - USD ($) $ in Thousands	9 Months Ended		12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Cumulative stock-based compensation	$ 15,171	$ 636	$ 883	$ 788
Cost of Revenue
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Cumulative stock-based compensation	181	3	5	14
Research and Development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Cumulative stock-based compensation	3,326	266	227	234
Sales and Marketing
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Cumulative stock-based compensation	2,828	119	189	176
General and Administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Cumulative stock-based compensation	$ 8,836	$ 248	$ 462	$ 364

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
State income tax expense	$ 25,000	$ 20,000
Valuation allowance	23,700,000	13,600,000
Operating loss carryforward	210.8
Operating loss carryforward, losses	$ 56,127,000	$ 43,405,000
Change in Unrecognized Tax Benefits	The Company does not believe it is reasonably possible that its unrecognized tax benefits will significantly change within the next twelve months.
Federal
Operating loss carryforward	$ 83
Expiration year	2017
Operating loss carryforward expiration beginning	$ 127.8
Open year examination	3 years
Federal | Minimum
Expiration year	2024
Federal | Maximum
Expiration year	2037
State
Operating loss carryforward	$ 141.6
Operating loss carryforward expiration beginning	133.5
Operating loss carryforward, losses	$ 8.2
Open year examination	4 years
State | Minimum
Expiration year	2020
State | Maximum
Expiration year	2040

Income Taxes - Summary of Effec

Income Taxes - Summary of Effective Tax Rate of the Provision for Income Taxes (Detail)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Federal statutory income tax rate	21.00%	21.00%
State taxes	7.80%	4.90%
Change in valuation allowance	(28.50%)	(27.20%)
Federal and state tax credits	0.90%	2.00%
Other	(1.20%)	(0.70%)
Total	0.00%	0.00%

Income Taxes - Summary of Compo

Income Taxes - Summary of Components of the Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Deferred tax assets:
Net operating loss carryforwards	$ 56,127	$ 43,405
Tax credits	8,777	6,993
Accrual and reserves	1,675	1,126
Tangible and intangible assets	15,888	7,117
Stock-based compensation	733	551
Gross deferred tax assets	82,865	59,192
Valuation allowance	(82,865)	(59,192)
Net deferred tax assets	0	0
Deferred tax liabilities:
Other intangibles	0	0
Net deferred tax	$ 0	$ 0

Income Taxes - Summary of Recon

Income Taxes - Summary of Reconciliation of the Total Unrecognized Tax Benefits (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)
Income Tax Disclosure [Abstract]
Balance, beginning of year	$ 8,385
Decrease related to current year positions	(7,601)
Increase related to current year positions	236
Balance, end of year	$ 1,020

Related-Party Transactions - Ad

Related-Party Transactions - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Related Party Transactions [Abstract]
Operating expenses with related parties	$ 300,000	$ 400,000
Amounts payable to related parties	$ 0	$ 1,000

Net Loss Per Share Attributab_3

Net Loss Per Share Attributable to Common Stockholders - Schedule of Outstanding Potentially Dilutive Shares were Excluded from Calculation of Diluted Net Loss Per Share (Detail) - shares	9 Months Ended		12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019	Dec. 31, 2018
Net Income Per Share [Line Items]
Anti-dilutive shares excluded from calculation of diluted net loss per share	4,810,000	23,001,000	22,906,017	22,553,271
Shares Committed under ESPP
Net Income Per Share [Line Items]
Anti-dilutive shares excluded from calculation of diluted net loss per share	5,000
Options to Purchase Common Stock
Net Income Per Share [Line Items]
Anti-dilutive shares excluded from calculation of diluted net loss per share	4,742,000	3,852,000	3,757,457	3,310,990
Warrants to Purchase Redeemable Convertible Preferred Stock
Net Income Per Share [Line Items]
Anti-dilutive shares excluded from calculation of diluted net loss per share		505,000	504,791	598,785
Warrant to Purchase Common Stock
Net Income Per Share [Line Items]
Anti-dilutive shares excluded from calculation of diluted net loss per share	63,000			8,860
Redeemable Convertible Preferred Stock
Net Income Per Share [Line Items]
Anti-dilutive shares excluded from calculation of diluted net loss per share		18,644,000	18,643,769	18,634,636

Subsequent Events - Additional

Subsequent Events - Additional Information (Detail) $ / shares in Units, $ in Thousands	1 Months Ended				3 Months Ended	9 Months Ended
	Dec. 31, 2023USD ($)	Mar. 31, 2021USD ($)	Sep. 30, 2020shares	May 31, 2020ft²	Mar. 31, 2020USD ($)$ / sharesshares	Sep. 30, 2020USD ($)shares	Jun. 30, 2021ft²	Dec. 31, 2019shares	Sep. 30, 2019USD ($)	Dec. 31, 2018shares
Common stock issued | shares			42,701,000			42,701,000		922,078		789,100
Settlement of accrued conversion rights						$ 41,763
Total future minimum lease payments									$ 8,800
Stockholders' Equity, Reverse Stock Split			In September 2020, the Company's board of directors and shareholders approved a certificate of amendment to the amended and restated certificate of incorporation to effect a reverse split of shares of the Company's common stock on a 7.9-for-one basis (the "Reverse Stock Split") effective as of September 8, 2020.			In September 2020, the Company's board of directors approved an amended and restated certificate of incorporation to effect a reverse split of shares of the Company's common stock on a 7.9-for-one basis (the "Reverse Stock Split") effective as of September 8, 2020.
MEXICO
Operating lease commencement date				2020-05
Operating lease expiring date				2026-08
Area of building possessed | ft²				48,437
MEXICO | Subsequent Event [Member]
Area of building possessed | ft²							38,750
Cash sequirity deposit		$ 1,700
Cash spent for renovation	$ 3,500	$ 3,500
Total future minimum lease payments	$ 3,200
Series E Preferred Stock [Member]
Convertible preferred stock issued | shares					57,781,875
Convertible preferred stock price per share | $ / shares					$ 2.20
Aggregate proceeds of convertible preferred stock					$ 127,100
Common stock issued | shares					4,849,933
Settlement of accrued conversion rights					$ 84,300

Description of Business - Addit

Description of Business - Additional Information (Detail) $ / shares in Units, $ in Thousands	Sep. 15, 2020USD ($)$ / sharesshares	Sep. 08, 2020USD ($)	Sep. 30, 2020USD ($)	Sep. 30, 2020USD ($)	Sep. 30, 2019USD ($)	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Description of Business [Line Items]
Entity incorporation date				May 5, 2003
Entity incorporation state				DE
Aggregate net proceeds from IPO	$ 254,800			$ 255,728
Offering costs, underwriting discounts and commissions expenses	$ 23,100
Cumulative stock-based compensation				$ 15,171	$ 636	$ 883	$ 788
Reverse stock split, description			In September 2020, the Company's board of directors and shareholders approved a certificate of amendment to the amended and restated certificate of incorporation to effect a reverse split of shares of the Company's common stock on a 7.9-for-one basis (the "Reverse Stock Split") effective as of September 8, 2020.	In September 2020, the Company's board of directors approved an amended and restated certificate of incorporation to effect a reverse split of shares of the Company's common stock on a 7.9-for-one basis (the "Reverse Stock Split") effective as of September 8, 2020.
Stock split conversion ratio		0.126582
Net loss				$ (89,449)	(48,853)	(68,299)	(49,780)
Accumulated deficit			$ (462,016)	(462,016)		(372,567)	(287,891)
Cash, cash equivalents and short-term investments			344,200	344,200		70,100
Restricted cash			33,311	33,311	$ 743	743	$ 151
Cash, cash equivalents, restricted cash and short-term investments			$ 377,500	377,500		$ 70,800
Stock Option
Description of Business [Line Items]
Cumulative stock-based compensation		$ 13,400		$ 13,400
IPO
Description of Business [Line Items]
Stock issued during the period | shares	10,294,000
Share price | $ / shares	$ 27
Underwriters
Description of Business [Line Items]
Stock issued during the period | shares	1,343,000

Balance Sheet Components - Sc_2

Balance Sheet Components - Schedule of Other Assets (Detail) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019	Dec. 31, 2018
Prepaid insurance, noncurrent	$ 1,878
Deposits	99	$ 82
Total other assets	$ 1,977	825	$ 558
Previously Reported [Member]
Total other assets		$ 82

Redeemable Convertible Prefe_12

Redeemable Convertible Preferred Stock and Stockholders' Equity (Deficit) - Additional Information (Detail) - $ / shares	Sep. 13, 2020	Sep. 30, 2020	Dec. 31, 2019
Class of Stock [Line Items]
Preferred stock, shares authorized		5,000,000	5,000,000
Preferred stock, par value		$ 0.001	$ 0.001
Preferred stock, shares issued		0	0
Preferred stock, shares outstanding		0	0
Common Stock
Class of Stock [Line Items]
Redeemable convertible preferred stock converted to common stock	25,958,000
Redeemable convertible preferred stock warrant liability
Class of Stock [Line Items]
Common stock issued on exercise of outstanding redeemable convertible preferred stock warrants	274,000

Stock-based Compensation - Addi

Stock-based Compensation - Additional Information (Detail) - USD ($)	Sep. 08, 2020	Sep. 30, 2020	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019	Dec. 31, 2018	Feb. 29, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock shares reserved for issuance					23,101,456	23,192,713
Stock-based compensation expense			$ 15,171,000	$ 636,000	$ 883,000	$ 788,000
Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options, new grant date fair value							$ 1,457,000
Stock-based compensation expense	$ 13,400,000		13,400,000
Unamortized deferred stock compensation amount		$ 10,000,000	$ 10,000,000
Outstanding stock options were fully vested		152,000	152,000
Estimated weighted average period over which unamortized share-based compensation are expected to be recognize			4 months 24 days
Stock Option | Employees and Executive Officers
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options outstanding		1,944,000	1,944,000
2020 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock shares reserved for issuance		3,665,000	3,665,000
Percentage of maximum number on common stock shares outstanding, additional shares available for issuance		4.00%
Shares awards granted		0	0
Contractual term			10 years
Percentage of fair market value of common stock			100.00%
Employees Share Purchase Plan (ESPP)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock shares reserved for issuance		687,000	687,000
Percentage of maximum number on common stock shares outstanding, additional shares available for issuance			1.00%
Percentage of fair market value of common stock		85.00%
Eligible compensation percentage to purchase common stock		15.00%	15.00%
ESPP offering period		6 months
ESPP initial offering date		Sep. 15, 2020
ESPP expiration date		Feb. 26, 2021

Net Loss Per Share Attributab_4

Net Loss Per Share Attributable to Common Stockholders - Schedule of Reconciliation of Numerator and Denominator Used in Calculation of Basic and Diluted Net Loss Per Share Attributable to Common Stockholders (Detail) - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended		12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019	Dec. 31, 2018
Numerator:
Net loss	$ (89,449)	$ (48,853)	$ (68,299)	$ (49,780)
Adjustment to redemption value on redeemable convertible preferred stock	(362)	(134,760)
Deemed dividend on settlement of accrued dividend	42,530
Gain on extinguishment of redeemable convertible preferred stock		117,598	117,597
Net loss attributable to common stockholders	$ (47,281)	$ (66,015)	$ (85,462)	$ (73,080)
Denominator:
Weighted-average shares of common stock, basic and diluted	7,508,000	838,000	858,254	725,337
Net loss per share attributable to common stockholders, basic and diluted	$ (6.30)	$ (78.77)	$ (99.58)	$ (100.75)