Eiger BioPharmaceuticals (EIGRQ) 10-Q 5 Nov 20 2020 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2020	Nov. 02, 2020
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2020
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q3
Trading Symbol	EIGR
Entity Registrant Name	Eiger BioPharmaceuticals, Inc.
Entity Central Index Key	0001305253
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Common Stock, Shares Outstanding		32,531,693
Entity Current Reporting Status	Yes
Entity Shell Company	false
Entity File Number	001-36183
Entity Tax Identification Number	33-0971591
Entity Address, Address Line One	2155 Park Boulevard
Entity Address, City or Town	Palo Alto
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	94306
City Area Code	650
Local Phone Number	272-6138
Entity Interactive Data Current	Yes
Title of 12(b) Security	Common Stock (par value $0.001 per share)
Security Exchange Name	NASDAQ
Entity Incorporation, State or Country Code	DE
Document Quarterly Report	true
Document Transition Report	false

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 51,993	$ 39,373
Debt securities, available-for-sale	73,341	55,621
Prepaid expenses and other current assets	9,608	5,390
Total current assets	134,942	100,384
Property and equipment, net	670	590
Operating lease right-of-use assets	1,300	1,654
Other assets	3,781	2,511
Total assets	140,693	105,139
Current liabilities:
Accounts payable	8,250	6,414
Accrued liabilities	7,062	10,001
Current portion of operating lease liabilities	565	534
Current portion of long-term debt, net	5,783
Total current liabilities	21,660	16,949
Long-term debt, net	25,200	30,390
Operating lease liabilities	883	1,320
Total liabilities	47,743	48,659
Stockholders’ equity:
Common stock	32	24
Additional paid-in capital	380,596	297,863
Accumulated other comprehensive income	16	42
Accumulated deficit	(287,694)	(241,449)
Total stockholders’ equity	92,950	56,480
Total liabilities and stockholders’ equity	$ 140,693	$ 105,139

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Operating expenses:
Research and development	$ 9,810	$ 14,059	$ 29,045	$ 39,863
General and administrative	5,027	4,247	15,141	12,529
Total operating expenses	14,837	18,306	44,186	52,392
Loss from operations	(14,837)	(18,306)	(44,186)	(52,392)
Interest expense	(906)	(884)	(2,681)	(2,518)
Interest income	76	585	629	1,598
Other expense, net	(13)	(11)	(7)	(20)
Net loss	$ (15,680)	$ (18,616)	$ (46,245)	$ (53,332)
Net loss per common share, basic and diluted	$ (0.52)	$ (0.76)	$ (1.74)	$ (2.40)
Weighted-average common shares outstanding, basic and diluted	29,879,135	24,437,451	26,639,201	22,261,715

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Statement Of Income And Comprehensive Income [Abstract]
Net loss	$ (15,680)	$ (18,616)	$ (46,245)	$ (53,332)
Other comprehensive (loss) gain:
Unrealized (loss) gain on available-for-sale debt securities, net	(29)	38	(26)	68
Comprehensive loss	$ (15,709)	$ (18,578)	$ (46,271)	$ (53,264)

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Accumulated Deficit [Member]
Balance at Dec. 31, 2018	$ 66,592	$ 19	$ 237,795	$ (25)	$ (171,197)
Balance, beginning of period, Shares at Dec. 31, 2018		19,211,759
Issuance of common stock upon exercise of stock options	65		65
Issuance of common stock upon exercise of stock options, Shares		41,546
Vesting of common stock issued under Product Development Agreement	56		56
Issuance of common stock upon ESPP purchase	59		59
Issuance of common stock upon ESPP purchase, Shares		7,138
Stock-based compensation expense	1,195		1,195
Unrealized gain (loss) on debt securities, net	30			30
Net loss	(17,189)				(17,189)
Balance at Mar. 31, 2019	50,808	$ 19	239,170	5	(188,386)
Balance, end of period, Shares at Mar. 31, 2019		19,260,443
Balance at Dec. 31, 2018	66,592	$ 19	237,795	(25)	(171,197)
Balance, beginning of period, Shares at Dec. 31, 2018		19,211,759
Unrealized gain (loss) on debt securities, net	68
Net loss	(53,332)
Balance at Sep. 30, 2019	71,659	$ 24	296,121	43	(224,529)
Balance, end of period, Shares at Sep. 30, 2019		24,494,185
Balance at Mar. 31, 2019	50,808	$ 19	239,170	5	(188,386)
Balance, beginning of period, Shares at Mar. 31, 2019		19,260,443
Issuance of common stock upon exercise of stock options	62		62
Issuance of common stock upon exercise of stock options, Shares		10,304
Vesting of common stock issued under Product Development Agreement	55		55
Issuance of common stock upon offering at-the-market, net of issuance costs	53,194	$ 5	53,189
Issuance of common stock upon offering at-the-market, net of issuance costs, Shares		5,175,000
Stock-based compensation expense	1,487		1,487
Net loss	(17,527)				(17,527)
Balance at Jun. 30, 2019	88,079	$ 24	293,963	5	(205,913)
Balance, end of period, Shares at Jun. 30, 2019		24,445,747
Issuance of common stock upon exercise of stock options	379		379
Issuance of common stock upon exercise of stock options, Shares		39,875
Vesting of common stock issued under Product Development Agreement	59		59
Issuance of common stock upon ESPP purchase	71		71
Issuance of common stock upon ESPP purchase, Shares		8,563
Stock-based compensation expense	1,649		1,649
Unrealized gain (loss) on debt securities, net	38			38
Net loss	(18,616)				(18,616)
Balance at Sep. 30, 2019	71,659	$ 24	296,121	43	(224,529)
Balance, end of period, Shares at Sep. 30, 2019		24,494,185
Balance at Dec. 31, 2019	56,480	$ 24	297,863	42	(241,449)
Balance, beginning of period, Shares at Dec. 31, 2019		24,523,381
Issuance of common stock upon exercise of stock options	30		30
Issuance of common stock upon exercise of stock options, Shares		2,895
Vesting of common stock issued under Product Development Agreement	53		53
Issuance of common stock upon ESPP purchase	83		83
Issuance of common stock upon ESPP purchase, Shares		11,332
Issuance of common stock upon offering at-the-market, net of issuance costs	191		191
Issuance of common stock upon offering at-the-market, net of issuance costs, Shares		32,751
Stock-based compensation expense	1,629		1,629
Unrealized gain (loss) on debt securities, net	(6)			(6)
Net loss	(15,239)				(15,239)
Balance at Mar. 31, 2020	43,221	$ 24	299,849	36	(256,688)
Balance, end of period, Shares at Mar. 31, 2020		24,570,359
Balance at Dec. 31, 2019	$ 56,480	$ 24	297,863	42	(241,449)
Balance, beginning of period, Shares at Dec. 31, 2019		24,523,381
Issuance of common stock upon exercise of stock options, Shares	61,700
Unrealized gain (loss) on debt securities, net	$ (26)
Net loss	(46,245)
Balance at Sep. 30, 2020	92,950	$ 32	380,596	16	(287,694)
Balance, end of period, Shares at Sep. 30, 2020		31,916,039
Balance at Mar. 31, 2020	43,221	$ 24	299,849	36	(256,688)
Balance, beginning of period, Shares at Mar. 31, 2020		24,570,359
Issuance of common stock upon exercise of stock options	490		490
Issuance of common stock upon exercise of stock options, Shares		58,805
Vesting of common stock issued under Product Development Agreement	55		55
Issuance of common stock upon offering at-the-market, net of issuance costs	28,580	$ 3	28,577
Issuance of common stock upon offering at-the-market, net of issuance costs, Shares		2,612,476
Stock-based compensation expense	1,462		1,462
Unrealized gain (loss) on debt securities, net	9			9
Net loss	(15,326)				(15,326)
Balance at Jun. 30, 2020	58,491	$ 27	330,433	45	(272,014)
Balance, end of period, Shares at Jun. 30, 2020		27,241,640
Vesting of common stock issued under Product Development Agreement	56		56
Issuance of common stock upon ESPP purchase	103		103
Issuance of common stock upon ESPP purchase, Shares		14,313
Issuance of common stock upon offering at-the-market, net of issuance costs	48,564	$ 5	48,559
Issuance of common stock upon offering at-the-market, net of issuance costs, Shares		4,660,086
Stock-based compensation expense	1,445		1,445
Unrealized gain (loss) on debt securities, net	(29)			(29)
Net loss	(15,680)				(15,680)
Balance at Sep. 30, 2020	$ 92,950	$ 32	$ 380,596	$ 16	$ (287,694)
Balance, end of period, Shares at Sep. 30, 2020		31,916,039

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Stockholders' Equity (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019
Statement Of Stockholders Equity [Abstract]
Issuance of common stock upon offering at-the-market, net of issuance costs	$ 1,575	$ 786	$ 221	$ 3,731

Condensed Consolidated Statem_5

Condensed Consolidated Statements of Cash Flow (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Operating activities
Net loss	$ (46,245)	$ (53,332)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	112	41
Amortization of debt securities discounts	(33)	(390)
Non-cash interest expense	593	535
Amortization of operating lease right-of-use assets	354	299
Common stock issued under Product Development Agreement	164	170
Stock-based compensation	4,536	4,331
Change in operating assets and liabilities:
Prepaid expenses and other current assets	(4,418)	(2,967)
Other assets	(1,270)	(2,952)
Accounts payable	1,836	3,178
Accrued liabilities	(2,893)	2,759
Operating lease liabilities	(406)	(315)
Net cash used in operating activities	(47,670)	(48,643)
Investing activities
Purchase of debt securities available-for-sale	(92,480)	(96,267)
Proceeds from maturities of debt securities available-for-sale	74,767	45,271
Purchase of property and equipment	(107)	(94)
Net cash used in investing activities	(17,820)	(51,090)
Financing activities
Proceeds from issuance of common stock upon public offering, net of issuance costs	77,404
Proceeds from issuance of common stock upon stock option exercises	520	506
Proceeds from issuance of common stock upon ESPP purchase	186	130
Proceeds from borrowings in connection with term loan, net of issuance costs		6,627
Repayment of accrued exit fee and second amendment fee		(913)
Repayment of term loan		(1,667)
Net cash provided by financing activities	78,110	57,877
Net increase (decrease) in cash and cash equivalents	12,620	(41,856)
Cash and cash equivalents at beginning of period	39,373	61,262
Cash and cash equivalents at end of period	51,993	19,406
Supplemental disclosure of cash flow information:
Interest paid	$ 2,089	1,944
Public Offering [Member]
Financing activities
Proceeds from issuance of common stock upon public offering, net of issuance costs		$ 53,194

Description of Business

Description of Business	9 Months Ended
	Sep. 30, 2020
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Description of Business	1. Description of Business Eiger BioPharmaceuticals, Inc. (the Company or Eiger) was incorporated in the State of Delaware on November 6, 2008. Eiger is a late-stage biopharmaceutical company focused on the development and commercialization of well-characterized drugs for life-threatening, rare and ultra-rare diseases with high unmet medical needs. Eiger has reported positive proof-of-concept clinical results across five programs: lonafarnib monotherapy in Hutchinson-Gilford Progeria Syndrome (HGPS or Progeria) and Progeroid Laminopathies, lonafarnib boosted with ritonavir in Hepatitis Delta Virus (HDV), peginterferon lambda (lambda) in HDV, and avexitide in both post-bariatric hypoglycemia (PBH) and congenital hyperinsulinism (CHI), all with first-in-class drugs, now under review for regulatory approvals, in Phase 3 clinical development, or advancing into Phase 3 development. Eiger’s lead clinical program is in Phase 3, developing lonafarnib, a first-in-class prenylation inhibitor, boosted with ritonavir, for the treatment of HDV infection, the most severe form of human viral hepatitis. The Company is also advancing lonafarnib monotherapy for treatment of Progeria and Progeroid Laminopathies, with a New Drug Application (NDA) and Marketing Authorization Application (MAA) under review by the U.S. Food and Drug Administration (FDA) and European Medicines Agency (EMA), respectively. Progeria and Progeroid Laminopathies are ultra-rare and rapidly fatal genetic conditions of accelerated aging in children. Lambda is the Company’s second program treating HDV and is Phase 3 ready. Lambda is a well-characterized, late-stage, first-in-class, type III interferon. The Company is also developing avexitide, a well-characterized peptide, as a treatment for PBH, a debilitating and potentially life-threatening condition for which there is currently no approved therapy, and as a treatment CHI, an ultra-rare pediatric metabolic disorder. The Company’s principal operations are based in Palo Alto, California and it operates in one segment. Liquidity As of September 30, 2020, the Company had $125.3 million of cash, cash equivalents and investments, comprised of $52.0 million of cash and cash equivalents and $73.3 million of debt securities available-for-sale. The Company had an accumulated deficit of $287.7 million and negative cash flows from operating activities as of September 30, 2020. As we continue to incur losses, our transition to profitability will depend on the successful development, approval, and commercialization of product candidates and on the achievement of sufficient revenues to support our cost structure. We may never achieve profitability, and unless and until we do, we will need to continue to raise additional capital. Management believes that the currently available resources will be sufficient to fund its operations for at least the next 12 months following the issuance date of these unaudited condensed consolidated financial statements. However, if our anticipated operating results are not achieved in future periods, we believe that planned expenditures may need to be reduced or we would be required to raise funding in order to fund our operations. Additionally, our ability to raise additional capital may be adversely impacted by potential worsening global economic conditions and the recent disruptions to, and volatility in, the credit and financial markets in the United States and worldwide resulting from the ongoing COVID-19 pandemic.

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2020
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Basis of Presentation The unaudited condensed consolidated financial statements include the accounts of Eiger BioPharmaceuticals, Inc. and its wholly owned subsidiaries, EBPI Merger Inc., EB Pharma LLC, Eiger BioPharmaceuticals Europe Limited, and EigerBio Europe Limited have been prepared in accordance with accounting principles generally accepted in the United States of America, (U.S. GAAP) and following the requirements of the Securities and Exchange Commission (the SEC) for interim reporting. As permitted under those rules, certain footnotes or other financial information that are normally required by U.S. GAAP can be condensed or omitted. These financial statements have been prepared on the same basis as the Company’s annual financial statements and, in the opinion of management, reflect all adjustments, consisting only of normal recurring adjustments, which are necessary for a fair statement of the Company’s financial information. These interim results are not necessarily indicative of the results to be expected for the nine months ended September 30, 2020 or for any other interim period or for any other future year. The balance sheet as of December 31, 2019, has been derived from audited consolidated financial statements at that date but does not include all of the information required by U.S. GAAP for complete financial statements. All intercompany balances and transactions have been eliminated in consolidation. The accompanying unaudited condensed consolidated financial statements and related financial information should be read in conjunction with the audited consolidated financial statements and the related notes thereto contained in the Company’s Annual Report on Form 10-K for the year ended December 31, 2019, filed with the Securities and Exchange Commission on March 13, 2020. Use of Estimates The preparation of unaudited condensed consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of expenses during the reporting period. On an ongoing basis, the Company evaluates its estimates, including those related to clinical trial accrued liabilities, stock-based compensation, operating lease liabilities and income taxes. The Company bases its estimates on historical experience and on various other market-specific and relevant assumptions that the Company believes to be reasonable under the circumstances. Actual results could differ from those estimates. Debt Securities Short-term securities consist of debt securities classified as available-for-sale and have maturities greater than 90 days, but less than 365 days from the date of acquisition. All short-term securities are carried at fair value based upon quoted market prices. Unrealized gains and losses on available-for-sale securities are excluded from earnings and are reported as a component of accumulated other comprehensive income (loss). The cost of available-for-sale securities sold is based on the specific-identification method . Accrued Research and Development Costs The Company accrues for estimated costs of research and development activities conducted by third-party service providers, which include the conduct of preclinical and clinical studies, and contract manufacturing activities. The Company records the estimated costs of research and development activities based upon the estimated amount of services provided but not yet invoiced and includes these costs in accrued liabilities in the unaudited condensed consolidated balance sheets and within research and development expense in the unaudited condensed consolidated statements of operations. The Company accrues for these costs based on factors such as estimates of the work completed and in accordance with agreements established with its third-party service providers. The Company makes judgments and estimates in determining the accrued liabilities balance in each reporting period. As actual costs become known, the Company adjusts its accrued liabilities. Leases The Company has a real estate lease for its office space in Palo Alto, California. The Company determines the initial classification and measurement of its right-of-use assets (ROU assets) and lease liabilities at the lease commencement date and thereafter if modified. The lease term includes any renewal options and termination options that the Company is reasonably assured to exercise. The present value of lease payments is determined by using the interest rate implicit in the lease, if that rate is readily determinable; otherwise, the Company uses its incremental borrowing rate. The incremental borrowing rate is determined by using the rate of interest that the Company would pay to borrow on a collateralized basis an amount equal to the lease payments for a similar term and in a similar economic environment. Rent expense for operating leases is recognized on a straight-line basis, unless the operating lease ROU assets have been impaired, over the reasonably assured lease term based on the total lease payments and is included in operating expenses in the unaudited condensed consolidated statements of operations. For operating leases that reflect impairment, the Company will recognize the amortization of the operating lease ROU assets on a straight-line basis over the remaining lease term with rent expense still included in general and administrative expenses in the unaudited condensed consolidated statements of operations. The Company elected the practical expedient to not separate lease and non-lease components. The Company’s non-lease components are primarily related to property maintenance and insurance, which varies based on future outcomes, and thus is recognized in general and administrative expenses when incurred. Net Loss per Share Basic net loss per share of common stock is calculated by dividing the net loss by the weighted average number of shares of common stock outstanding during the period, without consideration for potentially dilutive securities. Since the Company was in a loss position for all periods presented, diluted net loss per share is the same as basic net loss per share for all periods as the inclusion of all potential common shares outstanding would have been anti-dilutive. The following table sets forth the outstanding potentially dilutive securities which have been excluded in the calculation of diluted net loss per share because including such securities would be anti-dilutive (in common stock equivalent shares): Three Months Ended Nine Months Ended September 30, September 30, 2020 2019 2020 2019 Options to purchase common stock 3,774,680 2,862,520 3,774,680 2,862,520 Restricted stock units (unvested) 37,500 — 37,500 — Total 3,812,180 2,862,520 3,812,180 2,862,520 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) The adoption did not have a material impact on the Company’s unaudited condensed consolidated financial statements. In August 2018, the FASB issued ASU No. 2018-15, Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That is a Service Contract (Subtopic 350-40) The Company adopted this guidance on July 1, 2020 using the prospective approach. The adoption did not have a material impact on the Company’s condensed consolidated financial statements. Accounting Pronouncements Not Yet Adopted In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments—Credit Losses (Topic 326) Codification Improvements to Topic 326, Financial Instruments – Credit Losses, Topic 815, Derivatives and Hedging, and Topic 825, Financial Instruments, Financial Instruments – Credit Losses (Topic 326), to irrevocably elect to measure certain individual financial assets at fair value instead of amortized cost In November 2019, the FASB issued ASU No. 2019-10, Financial Instruments – Credit Losses (Topic 326), Derivatives and Hedging (Topic 815), and Leases (Topic 842) defers the effective date for ASU No. 2016-13 for smaller reporting companies to fiscal years beginning after December 15, 2022, including interim periods within those fiscal years. The Company is evaluating the impact of the guidance on its consolidated financial statements. In March 2020, the FASB issued ASU No. 2020-4, Reference Rate Reform (Topic 848) The pronouncement is effective for all entities as of March 12, 2020 through December 31, 2022. The Company plans to adopt upon the occurrence of such contract modification, but not later than December 31, 2022. The Company engaged in early-stage discussions with its lender and will assess the impact of the adoption once the contract is modified.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2020
Fair Value Disclosures [Abstract]
Fair Value Measurements	3. Fair Value Measurements Fair value accounting is applied for all financial assets and liabilities that are recognized or disclosed at fair value in the financial statements on a recurring basis (at least annually). As of September 30, 2020 and December 31, 2019 Assets and liabilities recorded at fair value on a recurring basis in the unaudited condensed consolidated balance sheets are categorized based upon the level of judgment associated with the inputs used to measure their fair values. Fair value is defined as the exchange price that would be received for an asset or an exit price that would be paid to transfer a liability in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. The authoritative guidance on fair value measurements establishes a three-tier fair value hierarchy for disclosure of fair value measurements as follows: Level 1 : Inputs are unadjusted, quoted prices in active markets for identical assets or liabilities at the measurement date; Level 2 : Inputs are observable, unadjusted quoted prices in active markets for similar assets or liabilities, unadjusted quoted prices for identical or similar assets or liabilities in markets that are not active, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the related assets or liabilities; and Level 3 : Unobservable inputs that are significant to the measurement of the fair value of the assets or liabilities that are supported by little or no market data. The Company’s money market funds are classified as Level 1 because they are valued using quoted market prices. The Company’s debt securities consist of available-for-sale securities and are classified as Level 2 because their value is based on valuations using significant inputs derived from or corroborated by observable market data. There were no There were no transfers into or out of Level 3 of the fair value hierarchy during the periods presented. The following tables present the fair value hierarchy for assets and liabilities measured at fair value (in thousands): September 30, 2020 Level 1 Level 2 Level 3 Total Financial assets: Money market funds $ 48,190 $ — $ — $ 48,190 Corporate debt securities — 18,868 — 18,868 Commercial paper — 5,492 — 5,492 U.S. treasury bills — 48,981 — 48,981 Total $ 48,190 $ 73,341 $ — $ 121,531 December 31, 2019 Level 1 Level 2 Level 3 Total Financial assets: Money market funds $ 35,854 $ — $ — $ 35,854 Corporate debt securities — 16,644 — 16,644 Commercial paper — 7,457 — 7,457 U.S. government Bonds — 31,520 — 31,520 Total $ 35,854 $ 55,621 $ — $ 91,475 There were no financial liabilities as of September 30, 2020 and December 31, 2019 The following tables summarize the estimated value of the Company’s cash equivalents and debt securities and the gross unrealized holding gains and losses (in thousands): September 30, 2020 Amortized cost Unrealized gain Unrealized loss Estimated Fair Value Cash equivalents: Money market funds $ 48,190 $ — $ — $ 48,190 Total cash equivalents $ 48,190 $ — $ — $ 48,190 Debt securities: Corporate debt securities $ 18,855 $ 18 $ (5 ) $ 18,868 Commercial paper 5,492 — — 5,492 U.S. treasury bills 48,978 3 — 48,981 Total debt securities $ 73,325 $ 21 $ (5 ) $ 73,341 December 31, 2019 Amortized cost Unrealized gain Unrealized loss Estimated Fair Value Cash equivalents: Money market funds $ 35,854 $ — $ — $ 35,854 Total cash equivalents $ 35,854 $ — $ — $ 35,854 Debt securities: Corporate debt securities $ 16,633 $ 11 $ — $ 16,644 Commercial paper 7,457 — — 7,457 U.S. government bonds 31,489 31 — 31,520 Total debt securities $ 55,579 $ 42 $ — $ 55,621 As of September 30, 2020 and December 31, 2019, the contractual maturity of the available-for-sale debt securities is less than one year. The Company periodically reviews the available-for-sale investments for impairment loss. The Company considers factors such as the duration, severity and the reason for the decline in value, the potential recovery period and its intent to sell. For debt securities, it also considers whether (i) it is more likely ot that the Company will be required to sell the debt securities before recovery of their amortized cost basis, and (ii) the amortized cost basis cannot be recovered as a result of credit losses. During the nine months ended September 30, 2020, the Company did not recognize any impairment losses. All debt securities with unrealized losses have been in a loss position for 12 months.

Consolidated Balance Sheet Comp

Consolidated Balance Sheet Components	9 Months Ended
	Sep. 30, 2020
Balance Sheet Related Disclosures [Abstract]
Consolidated Balance Sheet Components	4. Balance Sheet Components Prepaid Expenses and Other Current Assets Prepaid expenses and other current assets consist of the following (in thousands): September 30, December 31, 2020 2019 Prepaid contract manufacturing costs $ 6,033 $ 1,374 Prepaid research costs 1,995 1,627 Prepaid insurance 777 421 Other 803 1,968 Total prepaid expenses and other current assets $ 9,608 $ 5,390 Accrued Liabilities Accrued liabilities consist of the following (in thousands): September 30, December 31, 2020 2019 Contract research costs $ 3,309 $ 5,288 Compensation and related benefits 2,135 1,707 Contract manufacturing costs 956 2,510 Other 662 496 Total accrued liabilities $ 7,062 $ 10,001

Product Development Agreement

Product Development Agreement	9 Months Ended
	Sep. 30, 2020
Product Development Agreement [Abstract]
Product Development Agreement	5. Product Development Agreement Product Development Agreement On August 11, 2018, the Company entered into a Product Development Agreement and a First Project Agreement (the Product Agreements), pursuant to which the Company will receive development program support services for its HDV program. The services are to be provided from July 1, 2018 through the completion of the Phase 3 Clinical Study Reports and the subsequent new drug application (NDA) filing. As consideration, the Company has committed to pay fees of approximately $10.0 million in cash and stock over four years, including approximately $0.8 million for expert consultant fees and pass through costs to vendors, plus certain incentive-based regulatory milestone fees up to $1.0 million. As part of the aggregate payment, the Company issued 115,526 shares of common stock subject to quarterly vesting requirements related to successful performance of the services and achievement of budget timeline set forth in the Product Agreements. The Product Agreements can be terminated by either party due to material breach or by the Company without cause with Product Agreements. Additionally, as of September 30, 2020, the total unrecognized compensation expense related to unvested restricted shares was $0.3 million, which the Company expects to recognize over an estimated weighted-average period of years

Debt

Debt	9 Months Ended
	Sep. 30, 2020
Debt Disclosure [Abstract]
Debt	6. Debt In December 2016, the Company entered into an aggregate $25.0 million loan with Oxford Finance LLC (the Oxford Loan). The loan matures on July 1, 2021. The Company borrowed $15.0 million in December 2016 (Tranche A). In May 2018, the Company entered into an amendment to the Oxford Loan and borrowed $5.0 million (Tranche B). On August 3, 2018, the Company The Oxford Loan bears interest at a floating rate per annum equal to the greater of either the 30-day U.S. Dollar LIBOR reported in the Wall Street Journal plus 6.41% or 6.95%. The interest only period for borrowed funds was until February 1, 2019, followed by 30 equal monthly payments of principal plus accrued interest. At the time of final payment, the Company is required to pay an exit fee of 7.5% of the original principal balance of borrowed funds, or $1.9 million. In addition, at the time of final payment of Tranche B, the Company is required to pay an additional exit fee of $0.1 million. The Company recorded as a liability and debt discount the exit fee at the origination of the term loan. In addition, the Company incurred loan origination fees and debt issuance costs of $0.4 million which were recorded as a direct deduction from the carrying amount of the related debt liability as a debt discount. On March 5, 2019, the Company entered into the third amendment to the Oxford Loan (the Amended Oxford Loan) to refinance the Oxford Loan. The Amended Oxford Loan increased the aggregate amount available to be borrowed to $35.0 million and extended the maturity date to March 1, 2024. On March 5, 2019, prior to entering into the Amended Oxford Loan, the outstanding balance of the Oxford Loan was $23.3 million. At the time of entering into the Amended Oxford Loan, the Company borrowed an additional $6.7 million in principal under the Amended Oxford Loan, which increased the total amount borrowed to $30.0 million (Amended Tranche A). The remaining $5.0 million (Amended Tranche B) is available to the Company provided that certain milestones are achieved by February 2021. The Company does not currently expect to draw down Amended Tranche B. The Amended Oxford Loan bears interest at a floating rate per annum equal to the greater of either the 30-day U.S. Dollar LIBOR reported in the Wall Street Journal plus 6.64% or 9.15%. The Amended Oxford Loan has an interest only period until April 1, 2021, followed by 36 equal monthly payments of principal and interest. Upon the receipt of Amended Tranche B, the interest only period for borrowed funds will be extended by one year until April 1, 2022, followed by 24 equal monthly payments of principal plus accrued interest. the Company is required to pay an additional exit fee of $1.0 million The Company is also required to pay a 5.0 % success fee of the total amount drawn under the Amended Oxford Loan within 30 days following the FDA’s approval of the Company’s first product, excluding lonafarnib in Progeria and Progeroid Laminopathies. This fee is enforceable within 10 years from the funding of Amended Tranche A. The Company determined that the success fee met the scope exemption from derivative accounting and should be accounted for under the guidance for contingencies. Accordingly, the Company will record a liability for the success fee upon receipt of approval from the FDA. The Amended Oxford Loan includes contingent interest features and mandatory prepayment features upon an event of default that meet the definition of a derivative but were not bifurcated from the debt instrument as their fair value was deemed to be insignificant . In connection with the execution of the Oxford Loan, the Company agreed to certain customary representations and warranties. The refinancing of the term loan did not have a material impact on terms, conditions, representations, warranties, covenants or agreements set forth in the Oxford Loan. The loan is secured by the perfected first priority liens on the Company's assets, including a commitment by the Company to not allow any liens to be placed upon the Company’s intellectual property. The loan includes customary events of default, including failure to pay amounts due, breaches of covenants and warranties, material adverse effect events, certain cross defaults and judgments, and insolvency. If the Company is unable to comply with these covenants or if the Company defaults on any portion of the outstanding borrowings, the lenders can also impose a 5.0% penalty, restrict access to additional borrowings under the loan and security agreement, and accelerate the maturity of the debt. The Company is permitted to make voluntary prepayments of the Amended Oxford Loan with a prepayment fee, calculated as of the loan origination date, equal to (i) 2.0% of the loan prepaid during the first 12 months and (ii) 1.0% of the loan prepaid in months 13-24. The Company is required to make mandatory prepayments of the outstanding loan upon the acceleration by lender following the occurrence of an event of default, along with a payment of the final payment, the prepayment fee and any other obligations that are due and payable at the time of prepayment. The Company accounts for the amortization of the debt discount utilizing the effective interest method. Long-term debt and unamortized discount balances are as follows (in thousands): September 30, December 31, 2020 2019 Face value of long-term debt $ 30,000 $ 30,000 Exit fee 3,277 3,277 Unamortized debt discount associated with exit fee, debt issuance costs and loan origination fees (2,294 ) (2,887 ) Total long-term debt 30,983 30,390 Less: current portion of long-term debt, net 5,783 — Long-term debt, net $ 25,200 $ 30,390

Stock-Based Compensation

Stock-Based Compensation	9 Months Ended
	Sep. 30, 2020
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-Based Compensation	7. Stock-Based Compensation The following table summarizes stock option activity under the Company’s stock-based compensation plan during the nine months ended September 30, 2020 (in thousands, except option and share data): Shares Available for Grant Number of Options Weighted- Average Exercise Price Weighted- Average Remaining Contractual Life (in Years) Aggregate Intrinsic Value Outstanding as of December 31, 2019 823,598 2,767,617 $ 12.14 7.94 $ 8,218 Additional options authorized 1,226,169 — Granted (1,149,750 ) 1,149,750 $ 7.43 Restricted stock units granted (37,500 ) — Exercised — (61,700 ) $ 8.41 Canceled and forfeited 80,987 (80,987 ) $ 11.18 Outstanding as of September 30, 2020 943,504 3,774,680 $ 10.78 7.86 $ 2,921 Vested and exercisable as of September 30, 2020 1,856,770 $ 11.69 6.87 $ 1,245 During the three and nine months ended September 30, 2020, the Company granted stock options for the purchase of 85,000 and 1,149,750 shares of the Company’s common stock with a weighted-average grant date fair value of $7.18 and $4.78 per share, respectively. weighted-average grant date fair value of $7.18 and $9.01 per share, respectively. The Company records stock-based compensation of stock options granted by estimating the fair value of stock-based awards using the Black-Scholes option pricing model and amortizes the fair value of the stock-based awards granted over the applicable vesting period of the awards on a straight-line basis. The fair value of stock options was estimated using the following weighted-average assumptions: Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Expected term (in years) 6.08 6.02-6.08 5.27-6.08 5.27-6.08 Contractual term (in years) — — 10.00 10.00 Volatility 74.00% 74.19%-75.70% 73.00%-77.00% 74.19%-83.19% Risk free interest rate 0.39% 1.42%-1.90% 0.39%-1.37% 1.42%-2.57% Dividend yield — — — — Stock-Based Compensation Expense Total stock-based compensation expense recognized was as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Research and development $ 367 $ 559 $ 1,154 $ 1,366 General and administrative 1,078 1,090 3,382 2,965 Total $ 1,445 $ 1,649 $ 4,536 $ 4,331 As of September 30, 2020, the total unrecognized compensation expense related to unvested options was $12.1 million, which the Company expects to recognize over an estimated weighted average period of 2.7 years. Restricted Stock Units In the first quarter of 2020, the Company revised its non-employee director compensation policy to approve the granting of restricted stock units (RSUs) in accordance with the Restated 2013 Equity Incentive Plan (the Restated 2013 Plan). Each eligible director who has served for less than six months during the prior calendar year and continues to serve as a non-employee member of the board is granted RSUs, which are pro-rated for the period served during the prior calendar year. The RSUs granted to non-employee directors will vest on the one-year anniversary of the grant date, subject to the eligible director’s continuous services through the vesting date, and will vest in full upon a change in control, as defined under the Restated 2013 Plan. For RSU’s granted to employees during the nine months ended September 30, 2020, the vesting will begin on the one-year anniversary through the two-year anniversary of the grant date. The fair value of all RSUs are measured at the grant date based on the closing market price of the Company’s common stock and is recognized as stock-based compensation expense on a straight-line basis over the vesting period. There were no RSUs granted during the three months ended September 30, 2020. For the nine months ended September 30, 2020, 37,500 RSUs with a weighted-average grant date fair value of $6.95 per share. The Company recognized $0.1 million and $0.1 million in stock-based compensation expense for the three and nine months ended September 30, 2020, respectively, which is included in general and administrative expenses. As of September 30, 2020, the total unrecognized compensation expense related to unvested RSUs was $0.1 million, which the Company expects to recognize over an estimated weighted-average period of 0.6 years.

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2020
Income Tax Disclosure [Abstract]
Income Taxes	8. Income Taxes The Company did not record tax expense for the three and nine months ended September 30, 2020 and 2019 due to the Company’s loss position and full valuation allowance.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2020
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	9. Commitments and Contingencies Lease Agreements In October 2017, the Company entered into a non-cancelable operating facility lease agreement for 8,029 square feet of office space located at 2155 Park Blvd. in Palo Alto, California 94306. The lease commenced on March 1, 2018 and expires in February 2023 three-year The maturity of the Company’s operating lease liabilities were as follows (in thousands): Undiscounted lease payments September 30, 2020 Remaining in 2020 $ 160 2021 673 2022 662 2023 113 Total undiscounted payments 1,608 Less: imputed interest 160 Present value of future lease payments 1,448 Less: current portion of operating lease liabilities 565 Operating lease liabilities $ 883 Rent expense recognized for the Company’s operating leases was $0.2 million and $0.1 million for the three months ended September 30, 2020 and 2019, respectively, and $0.5 million and $0.4 million for the nine months ended September 30, 2020 and 2019, respectively. Under the terms of the lease agreements, the Company is also responsible for certain variable lease payments that are not included in the measurement of the lease liability. Variable lease payments for the operating leases were $23,000 and $21,400 for the three months ended September 30, 2020 and 2019, respectively, and $0.1 million and $0.1 million for the nine months ended September 30, 2020 and 2019. The operating cash outflows for the operating lease liabilities were $0.5 million and $0.5 million for the nine months ended September 30, 2020 and 2019, respectively. As of September 30, 2020 and December 31, 2019, the weighted-average remaining lease terms were 2.4 years and 3.1 years, and weighted-average discount rates were 9.15% and 9.15%, respectively.

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2020
Subsequent Events [Abstract]
Subsequent Events	10. Subsequent Events As of October 27, 2020, the Company completed the sale of common stock subject to its ATM financing facility with Jefferies LLC under the effective shelf statement filed on August 6, 2020, resulting in the total offering of 615,654 shares of common stock and net proceeds to the Company of $6.1 million, after deducting commissions.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2020
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The unaudited condensed consolidated financial statements include the accounts of Eiger BioPharmaceuticals, Inc. and its wholly owned subsidiaries, EBPI Merger Inc., EB Pharma LLC, Eiger BioPharmaceuticals Europe Limited, and EigerBio Europe Limited have been prepared in accordance with accounting principles generally accepted in the United States of America, (U.S. GAAP) and following the requirements of the Securities and Exchange Commission (the SEC) for interim reporting. As permitted under those rules, certain footnotes or other financial information that are normally required by U.S. GAAP can be condensed or omitted. These financial statements have been prepared on the same basis as the Company’s annual financial statements and, in the opinion of management, reflect all adjustments, consisting only of normal recurring adjustments, which are necessary for a fair statement of the Company’s financial information. These interim results are not necessarily indicative of the results to be expected for the nine months ended September 30, 2020 or for any other interim period or for any other future year. The balance sheet as of December 31, 2019, has been derived from audited consolidated financial statements at that date but does not include all of the information required by U.S. GAAP for complete financial statements. All intercompany balances and transactions have been eliminated in consolidation. The accompanying unaudited condensed consolidated financial statements and related financial information should be read in conjunction with the audited consolidated financial statements and the related notes thereto contained in the Company’s Annual Report on Form 10-K for the year ended December 31, 2019, filed with the Securities and Exchange Commission on March 13, 2020.
Use of Estimates	Use of Estimates The preparation of unaudited condensed consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of expenses during the reporting period. On an ongoing basis, the Company evaluates its estimates, including those related to clinical trial accrued liabilities, stock-based compensation, operating lease liabilities and income taxes. The Company bases its estimates on historical experience and on various other market-specific and relevant assumptions that the Company believes to be reasonable under the circumstances. Actual results could differ from those estimates.
Debt Securities	Debt Securities Short-term securities consist of debt securities classified as available-for-sale and have maturities greater than 90 days, but less than 365 days from the date of acquisition. All short-term securities are carried at fair value based upon quoted market prices. Unrealized gains and losses on available-for-sale securities are excluded from earnings and are reported as a component of accumulated other comprehensive income (loss). The cost of available-for-sale securities sold is based on the specific-identification method .
Accrued Research and Development Costs	Accrued Research and Development Costs The Company accrues for estimated costs of research and development activities conducted by third-party service providers, which include the conduct of preclinical and clinical studies, and contract manufacturing activities. The Company records the estimated costs of research and development activities based upon the estimated amount of services provided but not yet invoiced and includes these costs in accrued liabilities in the unaudited condensed consolidated balance sheets and within research and development expense in the unaudited condensed consolidated statements of operations. The Company accrues for these costs based on factors such as estimates of the work completed and in accordance with agreements established with its third-party service providers. The Company makes judgments and estimates in determining the accrued liabilities balance in each reporting period. As actual costs become known, the Company adjusts its accrued liabilities.
Leases	Leases The Company has a real estate lease for its office space in Palo Alto, California. The Company determines the initial classification and measurement of its right-of-use assets (ROU assets) and lease liabilities at the lease commencement date and thereafter if modified. The lease term includes any renewal options and termination options that the Company is reasonably assured to exercise. The present value of lease payments is determined by using the interest rate implicit in the lease, if that rate is readily determinable; otherwise, the Company uses its incremental borrowing rate. The incremental borrowing rate is determined by using the rate of interest that the Company would pay to borrow on a collateralized basis an amount equal to the lease payments for a similar term and in a similar economic environment. Rent expense for operating leases is recognized on a straight-line basis, unless the operating lease ROU assets have been impaired, over the reasonably assured lease term based on the total lease payments and is included in operating expenses in the unaudited condensed consolidated statements of operations. For operating leases that reflect impairment, the Company will recognize the amortization of the operating lease ROU assets on a straight-line basis over the remaining lease term with rent expense still included in general and administrative expenses in the unaudited condensed consolidated statements of operations. The Company elected the practical expedient to not separate lease and non-lease components. The Company’s non-lease components are primarily related to property maintenance and insurance, which varies based on future outcomes, and thus is recognized in general and administrative expenses when incurred.
Net Loss per Share	Net Loss per Share Basic net loss per share of common stock is calculated by dividing the net loss by the weighted average number of shares of common stock outstanding during the period, without consideration for potentially dilutive securities. Since the Company was in a loss position for all periods presented, diluted net loss per share is the same as basic net loss per share for all periods as the inclusion of all potential common shares outstanding would have been anti-dilutive. The following table sets forth the outstanding potentially dilutive securities which have been excluded in the calculation of diluted net loss per share because including such securities would be anti-dilutive (in common stock equivalent shares): Three Months Ended Nine Months Ended September 30, September 30, 2020 2019 2020 2019 Options to purchase common stock 3,774,680 2,862,520 3,774,680 2,862,520 Restricted stock units (unvested) 37,500 — 37,500 — Total 3,812,180 2,862,520 3,812,180 2,862,520
Recent Accounting Pronouncements	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) The adoption did not have a material impact on the Company’s unaudited condensed consolidated financial statements. In August 2018, the FASB issued ASU No. 2018-15, Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That is a Service Contract (Subtopic 350-40) The Company adopted this guidance on July 1, 2020 using the prospective approach. The adoption did not have a material impact on the Company’s condensed consolidated financial statements. Accounting Pronouncements Not Yet Adopted In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments—Credit Losses (Topic 326) Codification Improvements to Topic 326, Financial Instruments – Credit Losses, Topic 815, Derivatives and Hedging, and Topic 825, Financial Instruments, Financial Instruments – Credit Losses (Topic 326), to irrevocably elect to measure certain individual financial assets at fair value instead of amortized cost In November 2019, the FASB issued ASU No. 2019-10, Financial Instruments – Credit Losses (Topic 326), Derivatives and Hedging (Topic 815), and Leases (Topic 842) defers the effective date for ASU No. 2016-13 for smaller reporting companies to fiscal years beginning after December 15, 2022, including interim periods within those fiscal years. The Company is evaluating the impact of the guidance on its consolidated financial statements. In March 2020, the FASB issued ASU No. 2020-4, Reference Rate Reform (Topic 848) The pronouncement is effective for all entities as of March 12, 2020 through December 31, 2022. The Company plans to adopt upon the occurrence of such contract modification, but not later than December 31, 2022. The Company engaged in early-stage discussions with its lender and will assess the impact of the adoption once the contract is modified.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	9 Months Ended
	Sep. 30, 2020
Accounting Policies [Abstract]
Schedule of Antidilutive Securities Excluded from Computation of Earnings per Share	The following table sets forth the outstanding potentially dilutive securities which have been excluded in the calculation of diluted net loss per share because including such securities would be anti-dilutive (in common stock equivalent shares): Three Months Ended Nine Months Ended September 30, September 30, 2020 2019 2020 2019 Options to purchase common stock 3,774,680 2,862,520 3,774,680 2,862,520 Restricted stock units (unvested) 37,500 — 37,500 — Total 3,812,180 2,862,520 3,812,180 2,862,520

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2020
Fair Value Disclosures [Abstract]
Summary of Assets and Liabilities Measured at Fair Value	The following tables present the fair value hierarchy for assets and liabilities measured at fair value (in thousands): September 30, 2020 Level 1 Level 2 Level 3 Total Financial assets: Money market funds $ 48,190 $ — $ — $ 48,190 Corporate debt securities — 18,868 — 18,868 Commercial paper — 5,492 — 5,492 U.S. treasury bills — 48,981 — 48,981 Total $ 48,190 $ 73,341 $ — $ 121,531 December 31, 2019 Level 1 Level 2 Level 3 Total Financial assets: Money market funds $ 35,854 $ — $ — $ 35,854 Corporate debt securities — 16,644 — 16,644 Commercial paper — 7,457 — 7,457 U.S. government Bonds — 31,520 — 31,520 Total $ 35,854 $ 55,621 $ — $ 91,475
Summary of Estimated Value of Cash Equivalents and Debt Securities and Gross Unrealized Holding Gains and Losses	The following tables summarize the estimated value of the Company’s cash equivalents and debt securities and the gross unrealized holding gains and losses (in thousands): September 30, 2020 Amortized cost Unrealized gain Unrealized loss Estimated Fair Value Cash equivalents: Money market funds $ 48,190 $ — $ — $ 48,190 Total cash equivalents $ 48,190 $ — $ — $ 48,190 Debt securities: Corporate debt securities $ 18,855 $ 18 $ (5 ) $ 18,868 Commercial paper 5,492 — — 5,492 U.S. treasury bills 48,978 3 — 48,981 Total debt securities $ 73,325 $ 21 $ (5 ) $ 73,341 December 31, 2019 Amortized cost Unrealized gain Unrealized loss Estimated Fair Value Cash equivalents: Money market funds $ 35,854 $ — $ — $ 35,854 Total cash equivalents $ 35,854 $ — $ — $ 35,854 Debt securities: Corporate debt securities $ 16,633 $ 11 $ — $ 16,644 Commercial paper 7,457 — — 7,457 U.S. government bonds 31,489 31 — 31,520 Total debt securities $ 55,579 $ 42 $ — $ 55,621

Consolidated Balance Sheet Co_2

Consolidated Balance Sheet Components (Tables)	9 Months Ended
	Sep. 30, 2020
Balance Sheet Related Disclosures [Abstract]
Schedule of Prepaid Expenses and Other Current Assets	Prepaid Expenses and Other Current Assets Prepaid expenses and other current assets consist of the following (in thousands): September 30, December 31, 2020 2019 Prepaid contract manufacturing costs $ 6,033 $ 1,374 Prepaid research costs 1,995 1,627 Prepaid insurance 777 421 Other 803 1,968 Total prepaid expenses and other current assets $ 9,608 $ 5,390
Schedule of Components of Accrued Liabilities	Accrued Liabilities Accrued liabilities consist of the following (in thousands): September 30, December 31, 2020 2019 Contract research costs $ 3,309 $ 5,288 Compensation and related benefits 2,135 1,707 Contract manufacturing costs 956 2,510 Other 662 496 Total accrued liabilities $ 7,062 $ 10,001

Debt (Tables)

Debt (Tables)	9 Months Ended
	Sep. 30, 2020
Debt Disclosure [Abstract]
Schedule of Long-Term Debt and Unamortized Discount Balances	Long-term debt and unamortized discount balances are as follows (in thousands): September 30, December 31, 2020 2019 Face value of long-term debt $ 30,000 $ 30,000 Exit fee 3,277 3,277 Unamortized debt discount associated with exit fee, debt issuance costs and loan origination fees (2,294 ) (2,887 ) Total long-term debt 30,983 30,390 Less: current portion of long-term debt, net 5,783 — Long-term debt, net $ 25,200 $ 30,390

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2020
Stock Option Activity	The following table summarizes stock option activity under the Company’s stock-based compensation plan during the nine months ended September 30, 2020 (in thousands, except option and share data): Shares Available for Grant Number of Options Weighted- Average Exercise Price Weighted- Average Remaining Contractual Life (in Years) Aggregate Intrinsic Value Outstanding as of December 31, 2019 823,598 2,767,617 $ 12.14 7.94 $ 8,218 Additional options authorized 1,226,169 — Granted (1,149,750 ) 1,149,750 $ 7.43 Restricted stock units granted (37,500 ) — Exercised — (61,700 ) $ 8.41 Canceled and forfeited 80,987 (80,987 ) $ 11.18 Outstanding as of September 30, 2020 943,504 3,774,680 $ 10.78 7.86 $ 2,921 Vested and exercisable as of September 30, 2020 1,856,770 $ 11.69 6.87 $ 1,245
Summary of Non-cash Stock Based Compensation Expense	Total stock-based compensation expense recognized was as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Research and development $ 367 $ 559 $ 1,154 $ 1,366 General and administrative 1,078 1,090 3,382 2,965 Total $ 1,445 $ 1,649 $ 4,536 $ 4,331
Employees and Non Employees Stock Option [Member]
Weighted-average assumptions used in Black-Scholes Model to estimate fair value of stock options granted	The fair value of stock options was estimated using the following weighted-average assumptions: Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Expected term (in years) 6.08 6.02-6.08 5.27-6.08 5.27-6.08 Contractual term (in years) — — 10.00 10.00 Volatility 74.00% 74.19%-75.70% 73.00%-77.00% 74.19%-83.19% Risk free interest rate 0.39% 1.42%-1.90% 0.39%-1.37% 1.42%-2.57% Dividend yield — — — —

Commitments and Contingencies (

Commitments and Contingencies (Tables)	9 Months Ended
	Sep. 30, 2020
Commitments And Contingencies Disclosure [Abstract]
Maturity of Operating Leases Liabilities	The maturity of the Company’s operating lease liabilities were as follows (in thousands): Undiscounted lease payments September 30, 2020 Remaining in 2020 $ 160 2021 673 2022 662 2023 113 Total undiscounted payments 1,608 Less: imputed interest 160 Present value of future lease payments 1,448 Less: current portion of operating lease liabilities 565 Operating lease liabilities $ 883

Description of Business - Addit

Description of Business - Additional Information (Detail) $ in Thousands	9 Months Ended
	Sep. 30, 2020USD ($)Segment	Dec. 31, 2019USD ($)
Description Of Business [Abstract]
Entity incorporation, date of incorporation	Nov. 6, 2008
Number of operating segments | Segment	1
Cash, Cash Equivalents, and Investments	$ 125,300
Cash and cash equivalents	51,993	$ 39,373
Debt securities, available-for-sale	73,341	55,621
Accumulated deficit	$ (287,694)	$ (241,449)

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Schedule of Antidilutive Securities Excluded from Computation of Earnings per Share (Detail) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities	3,812,180	2,862,520	3,812,180	2,862,520
Options Granted to Employees and Non Employees [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities	3,774,680	2,862,520	3,774,680	2,862,520
Restricted Stock Units, Unvested [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities	37,500		37,500

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Detail) - USD ($)	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial assets	$ 121,531,000	$ 91,475,000
Financial liabilities	0	0
Transfers between levels	0	$ 0
Other-than-temporary impairment losses	$ 0
Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available- for-sale of debt securities contractual maturity	1 year	1 year
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial assets	$ 0	$ 0
Financial liabilities	$ 0	$ 0

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Assets and Liabilities Measured at Fair Value (Detail) - USD ($)	Sep. 30, 2020	Dec. 31, 2019
Financial assets:
Assets, Fair Value	$ 121,531,000	$ 91,475,000
U.S. Treasury Bills [Member]
Financial assets:
Assets, Fair Value	48,981,000
Corporate Debt Securities [Member]
Financial assets:
Assets, Fair Value	18,868,000	16,644,000
U.S. Government Bonds [Member]
Financial assets:
Assets, Fair Value		31,520,000
Money Market Funds [Member]
Financial assets:
Assets, Fair Value	48,190,000	35,854,000
Commercial Paper [Member]
Financial assets:
Assets, Fair Value	5,492,000	7,457,000
Level 1 [Member]
Financial assets:
Assets, Fair Value	48,190,000	35,854,000
Level 1 [Member] | Money Market Funds [Member]
Financial assets:
Assets, Fair Value	48,190,000	35,854,000
Level 2 [Member]
Financial assets:
Assets, Fair Value	73,341,000	55,621,000
Level 2 [Member] | U.S. Treasury Bills [Member]
Financial assets:
Assets, Fair Value	48,981,000
Level 2 [Member] | Corporate Debt Securities [Member]
Financial assets:
Assets, Fair Value	18,868,000	16,644,000
Level 2 [Member] | U.S. Government Bonds [Member]
Financial assets:
Assets, Fair Value		31,520,000
Level 2 [Member] | Commercial Paper [Member]
Financial assets:
Assets, Fair Value	5,492,000	7,457,000
Level 3 [Member]
Financial assets:
Assets, Fair Value	$ 0	$ 0

Fair Value Measurements - Estim

Fair Value Measurements - Estimated Value of Cash Equivalents and Debt Securities and Gross Unrealized Holding Gains and Losses (Detail) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Cash Equivalents and Investment Securities [Line Items]
Cash equivalents, Amortized cost	$ 48,190	$ 35,854
Cash equivalents, Estimated Fair Value	48,190	35,854
Debt securities, Amortized cost	73,325	55,579
Debt securities, Unrealized gain	21	42
Debt securities, Unrealized loss	(5)
Debt securities, Estimated Fair Value	73,341	55,621
U.S. Treasury Bills [Member]
Cash Equivalents and Investment Securities [Line Items]
Debt securities, Amortized cost	48,978
Debt securities, Unrealized gain	3
Debt securities, Estimated Fair Value	48,981
Corporate Debt Securities [Member]
Cash Equivalents and Investment Securities [Line Items]
Debt securities, Amortized cost	18,855	16,633
Debt securities, Unrealized gain	18	11
Debt securities, Unrealized loss	(5)
Debt securities, Estimated Fair Value	18,868	16,644
U.S. Government Bonds [Member]
Cash Equivalents and Investment Securities [Line Items]
Debt securities, Amortized cost		31,489
Debt securities, Unrealized gain		31
Debt securities, Estimated Fair Value		31,520
Money Market Funds [Member]
Cash Equivalents and Investment Securities [Line Items]
Cash equivalents, Amortized cost	48,190	35,854
Cash equivalents, Estimated Fair Value	48,190	35,854
Commercial Paper [Member]
Cash Equivalents and Investment Securities [Line Items]
Debt securities, Amortized cost	5,492	7,457
Debt securities, Estimated Fair Value	$ 5,492	$ 7,457

Consolidated Balance Sheet Co_3

Consolidated Balance Sheet Components - Schedule of Prepaid Expenses and Other Current Assets (Detail) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Prepaid Expense And Other Assets Current [Abstract]
Prepaid contract manufacturing costs	$ 6,033	$ 1,374
Prepaid research costs	1,995	1,627
Prepaid insurance	777	421
Other	803	1,968
Total prepaid expenses and other current assets	$ 9,608	$ 5,390

Consolidated Balance Sheet Co_4

Consolidated Balance Sheet Components - Schedule of Components of Accrued Liabilities (Detail) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Payables And Accruals [Abstract]
Contract research costs	$ 3,309	$ 5,288
Compensation and related benefits	2,135	1,707
Contract manufacturing costs	956	2,510
Other	662	496
Total accrued liabilities	$ 7,062	$ 10,001

Product Development Agreement -

Product Development Agreement - Additional Information (Detail) - USD ($) $ in Thousands	Aug. 11, 2018	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Research and development		$ 9,810	$ 14,059	$ 29,045	$ 39,863
Weighted-average period for recognition (in years)				2 years 8 months 12 days
Product Development Agreement [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Product development fees	$ 10,000
Expert consultant fees and pass through costs	800
Incentive-based regulatory milestone fees	$ 1,000
Number of common stock issued subject to quarterly vesting requirements	115,526
Product agreement termination notice period	90 days
Research and development		100		$ 200
Unrecognised compensation expense related to unvested restricted shares		$ 300		$ 300
Weighted-average period for recognition (in years)				1 year 6 months

Debt - Additional Information (

Debt - Additional Information (Detail) - USD ($) $ in Thousands	Mar. 05, 2019	Jun. 30, 2020	Sep. 30, 2020	Dec. 31, 2019	Aug. 03, 2018	May 31, 2018	Dec. 31, 2016
Debt Instrument [Line Items]
Face value of term loan			$ 30,000	$ 30,000
Loan final repayment exit fees payable			$ (3,277)	$ (3,277)
Loan agreement, covenant noncompliance penalty			5.00%
Loan agreement, covenant description			The loan includes customary events of default, including failure to pay amounts due, breaches of covenants and warranties, material adverse effect events, certain cross defaults and judgments, and insolvency. If the Company is unable to comply with these covenants or if the Company defaults on any portion of the outstanding borrowings, the lenders can also impose a 5.0% penalty, restrict access to additional borrowings under the loan and security agreement,
Loan agreement, covenant compliance			and accelerate the maturity of the debt.
Oxford Loan [Member]
Debt Instrument [Line Items]
Loan agreement, aggregate borrowing capacity							$ 25,000
Loan, maturity period		Jul. 1, 2021
Loan agreement, floating rate terms			floating rate per annum equal to the greater of either the 30-day U.S. Dollar LIBOR reported in the Wall Street Journal plus 6.41% or 6.95%.
Principal and interest payment period			30 months
Percentage of exit fee on principal balance			7.50%
Loan final repayment exit fees payable			$ 1,900
Loan origination fees and debt issuance costs							400
Repayments of loan agreement exit fee		$ 900
Oxford Loan [Member] | Minimum [Member]
Debt Instrument [Line Items]
Loan agreement, interest rate			6.95%
Oxford Loan [Member] | LIBOR [Member]
Debt Instrument [Line Items]
Loan agreement, percentage to be added to the interest rate under condition			6.41%
Oxford Loan [Member] | Tranche A [Member]
Debt Instrument [Line Items]
Face value of term loan							$ 15,000
Oxford Loan [Member] | Tranche B [Member]
Debt Instrument [Line Items]
Loan final repayment exit fees payable			$ 100
Amendment [Member] | Tranche B [Member]
Debt Instrument [Line Items]
Face value of term loan						$ 5,000
Amendment [Member] | Tranche C [Member]
Debt Instrument [Line Items]
Face value of term loan					$ 5,000
Amended Oxford Loan [Member]
Debt Instrument [Line Items]
Loan agreement, aggregate borrowing capacity	$ 35,000
Loan, maturity period		Mar. 1, 2024
Loan agreement, floating rate terms			floating rate per annum equal to the greater of either the 30-day U.S. Dollar LIBOR reported in the Wall Street Journal plus 6.64% or 9.15%
Principal and interest payment period			36 months
Percentage of exit fee on principal balance			7.50%
Loan final repayment exit fees payable			$ 2,300
Loan origination fees and debt issuance costs			200
Loan outstanding	23,300
Borrowings from loan agreement	6,700
Loan final repayment additional exit fees payable			$ 1,000
Prepayment of loan fee, description			calculated as of the loan origination date, equal to (i) 2.0% of the loan prepaid during the first 12 months and (ii) 1.0% of the loan prepaid in months 13-24.
Amended Oxford Loan [Member] | Loan Prepaid During First 12 Months [Member]
Debt Instrument [Line Items]
Debt instrument prepayment fee percentage			2.00%
Amended Oxford Loan [Member] | Loan Prepaid During 13 to 24 Months [Member]
Debt Instrument [Line Items]
Debt instrument prepayment fee percentage			1.00%
Amended Oxford Loan [Member] | Food and Drug Administration [Member]
Debt Instrument [Line Items]
Percentage of success fee			5.00%
Success fees payable maximum period after approval			30 days
Amended Oxford Loan [Member] | Minimum [Member]
Debt Instrument [Line Items]
Loan agreement, interest rate			9.15%
Amended Oxford Loan [Member] | LIBOR [Member]
Debt Instrument [Line Items]
Loan agreement, percentage to be added to the interest rate under condition			6.64%
Amended Oxford Loan [Member] | Amended Tranche A [Member]
Debt Instrument [Line Items]
Loan agreement, aggregate borrowing capacity	30,000
Amended Oxford Loan [Member] | Amended Tranche A [Member] | Food and Drug Administration [Member]
Debt Instrument [Line Items]
Fee payable maximum period from funding			10 years
Amended Oxford Loan [Member] | Amended Tranche B [Member]
Debt Instrument [Line Items]
Principal and interest payment period			24 months
Loan agreement, remaining borrowing capacity	$ 5,000
Extended term of interest only payment period			1 year

Debt - Schedule of Long-Term De

Debt - Schedule of Long-Term Debt and Unamortized Discount Balances (Detail) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Debt Disclosure [Abstract]
Face value of long-term debt	$ 30,000	$ 30,000
Exit fee	3,277	3,277
Unamortized debt discount associated with exit fee, debt issuance costs and loan origination fees	(2,294)	(2,887)
Total long-term debt	30,983	30,390
Current portion of long-term debt, net	5,783
Long-term debt, net	$ 25,200	$ 30,390

Stock-Based Compensation - Stoc

Stock-Based Compensation - Stock Option Activity (Detail) $ / shares in Units, $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2020USD ($)$ / sharesshares	Dec. 31, 2019USD ($)$ / sharesshares
Sharebased Compensation Arrangement By Sharebased Payment Award Options Outstanding Weighted Average Exercise Price And Additional Disclosures [Abstract]
Shares Available for Grant, Outstanding, Beginning balance	823,598
Shares Available for Grant, Additional options authorized	1,226,169
Shares Available for Grant, Granted	(1,149,750)
Shares Available for Grant, Restricted stock units granted	(37,500)
Shares Available for Grant, Canceled and forfeited	80,987
Shares Available for Grant, Outstanding, Ending balance	943,504	823,598
Number of Options, Outstanding, Beginning balance	2,767,617
Number of Options, Granted	1,149,750
Number of Options, Exercised	(61,700)
Number of Options, Canceled and forfeited	(80,987)
Number of Options, Outstanding, Ending balance	3,774,680	2,767,617
Number of Options, Vested and exercisable	1,856,770
Weighted-Average Exercise Price, Outstanding, Beginning balance | $ / shares	$ 12.14
Weighted-Average Exercise Price, Granted | $ / shares	7.43
Weighted-Average Exercise Price, Exercised | $ / shares	8.41
Weighted-Average Exercise Price, Canceled and forfeited | $ / shares	11.18
Weighted-Average Exercise Price, Outstanding, Ending balance | $ / shares	10.78	$ 12.14
Weighted-Average Exercise Price, vested and exercisable | $ / shares	$ 11.69
Weighted Average Remaining Contractual Life, Ending balance	7 years 10 months 9 days	7 years 11 months 8 days
Weighted Average Remaining Contractual Life, vested and exercisable	6 years 10 months 13 days
Aggregate Intrinsic Value | $	$ 2,921	$ 8,218
Aggregate Intrinsic Value, Vested and exercisable | $	$ 1,245

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options granted			1,149,750
Total unrecognized compensation expense	$ 12,100		$ 12,100
Weighted-average period for recognition (in years)			2 years 8 months 12 days
Stock-based compensation expense	$ 1,445	$ 1,649	$ 4,536	$ 4,331
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options granted	85,000	217,000	1,149,750	1,079,750
Weighted-average grant date fair value of employee option grants	$ 7.18	$ 7.18	$ 4.78	$ 9.01
Restricted Stock Units, Unvested [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options granted	0		37,500
Weighted-average grant date fair value of employee option grants			$ 6.95
Total unrecognized compensation expense	$ 100		$ 100
Weighted-average period for recognition (in years)			7 months 6 days
Stock-based compensation expense	$ 100		$ 100

Stock-Based Compensation - Weig

Stock-Based Compensation - Weighted-average assumptions used in Black-Scholes Model to estimate fair value of stock options granted (Detail)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Contractual term (in years)			7 years 10 months 9 days		7 years 11 months 8 days
Employees Stock Option [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)	6 years 28 days	6 years 7 days	5 years 3 months 7 days	5 years 3 months 7 days
Employees Stock Option [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)		6 years 29 days	6 years 28 days	6 years 29 days
Non Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Contractual term (in years)			10 years	10 years
Employees and Non Employees Stock Option [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Volatility, minimum	74.00%	74.19%	73.00%	74.19%
Risk free interest rate, minimum	0.39%	1.42%	0.39%	1.42%
Employees and Non Employees Stock Option [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Volatility, maximum		75.70%	77.00%	83.19%
Risk free interest rate, maximum		1.90%	1.37%	2.57%

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Non-cash Stock Based Compensation Expense (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	$ 1,445	$ 1,649	$ 4,536	$ 4,331
Research and Development [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	367	559	1,154	1,366
General and Administrative [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	$ 1,078	$ 1,090	$ 3,382	$ 2,965

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Income Tax Disclosure [Abstract]
Tax expense	$ 0	$ 0	$ 0	$ 0

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail)	1 Months Ended	3 Months Ended		9 Months Ended
	Oct. 31, 2017USD ($)ft²	Sep. 30, 2020USD ($)	Sep. 30, 2019USD ($)	Sep. 30, 2020USD ($)	Sep. 30, 2019USD ($)	Dec. 31, 2019
Other Commitments [Line Items]
Rent expense recognized for company's operating leases		$ 200,000	$ 100,000	$ 500,000	$ 400,000
Variable lease payments for operating leases		$ 23,000	$ 21,400	100,000	100,000
Operating cash outflows for operating lease liabilities				$ 500,000	$ 500,000
Weighted-average remaining lease term		2 years 4 months 24 days		2 years 4 months 24 days		3 years 1 month 6 days
Weighted-average discount rate		9.15%		9.15%		9.15%
Palo Alto, California [Member]
Other Commitments [Line Items]
Total leased space | ft²	8,029
Lease commencement date	Mar. 1, 2018
Long-term operating lease expiry period month and year	Feb. 28, 2023
Lease renewal term	3 years
Security deposit of collateral for lease	$ 300,000

Commitments and Contingencies_2

Commitments and Contingencies - Maturity of Operating Leases Liabilities (Detail) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Commitments And Contingencies Disclosure [Abstract]
Operating leases minimum payments, 2020	$ 160
Operating leases minimum payments, 2021	673
Operating leases minimum payments, 2022	662
Operating leases minimum payments, 2023	113
Total undiscounted payments	1,608
Less: imputed interest	160
Present value of future lease payments	1,448
Less: current portion of operating lease liabilities	565	$ 534
Operating lease liabilities	$ 883	$ 1,320

Subsequent Events - Additional

Subsequent Events - Additional Information (Detail) - USD ($) $ in Thousands	Oct. 27, 2020	Sep. 30, 2020
Subsequent Event [Line Items]
Net proceeds from sale of common stock, after deducting commissions		$ 77,404
Subsequent Event [Member] | Jefferies LLC [Member]
Subsequent Event [Line Items]
Issuance of common stock upon offering at-the-market financing facility	615,654
Net proceeds from sale of common stock, after deducting commissions	$ 6,100