Allena Pharmaceuticals (ALNAQ) 10-Q 5 Aug 20 2020 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2020	Jul. 31, 2020
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2020
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q2
Trading Symbol	ALNA
Entity Registrant Name	Allena Pharmaceuticals, Inc.
Entity Central Index Key	0001624658
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Shell Company	false
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	true
Entity Common Stock, Shares Outstanding		38,118,925
Entity File Number	001-38268
Entity Tax Identification Number	45-2729920
Entity Address, Address Line One	One Newton Executive Park
Entity Address, Address Line Two	Suite 202
Entity Address, City or Town	Newton
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02462
City Area Code	617
Local Phone Number	467-4577
Title of 12(b) Security	Common Stock, par value $0.001 per share
Security Exchange Name	NASDAQ
Document Quarterly Report	true
Document Transition Report	false
Entity Incorporation, State or Country Code	DE

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (unaudited) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 26,453	$ 30,007
Prepaid expenses and other current assets	1,923	3,028
Total current assets	28,376	33,035
Property and equipment, net	318	401
Operating lease assets	291	549
Other assets	123	123
Total assets	29,108	34,108
Current liabilities:
Accounts payable	570	3,048
Loan payable, net of discount	3,992	3,992
Accrued expenses and other current liabilities	1,885	3,370
Operating lease liabilities, net of discount	296	498
Total current liabilities	6,743	10,908
Loan payable, net of current portion and discount	3,992	5,988
Operating lease liabilities, net of current portion		14
Total liabilities	10,735	16,910
Commitments and contingencies (Note 7)
Stockholders’ equity:
Undesignated preferred stock, $0.001 par value; 5,000,000 shares authorized; no shares issued or outstanding
Common stock, $0.001 par value; 125,000,000 shares authorized; 32,224,734 and 24,735,009 shares issued and outstanding at June 30, 2020 and December 31, 2019, respectively	32	25
Additional paid-in capital	197,846	182,117
Accumulated deficit	(179,505)	(164,944)
Total stockholders’ equity	18,373	17,198
Total liabilities and stockholders’ equity	$ 29,108	$ 34,108

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) (unaudited) - $ / shares	Jun. 30, 2020	Dec. 31, 2019
Statement Of Financial Position [Abstract]
Undesignated preferred stock, par value	$ 0.001	$ 0.001
Undesignated preferred stock, shares authorized	5,000,000	5,000,000
Undesignated preferred stock, shares issued	0	0
Undesignated preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	125,000,000	125,000,000
Common stock, shares issued	32,224,734	24,735,009
Common stock, shares outstanding	32,224,734	24,735,009

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Loss (unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Operating expenses:
Research and development	$ 3,808	$ 8,589	$ 8,454	$ 17,717
General and administrative	2,751	2,746	5,629	5,177
Total operating expenses	6,559	11,335	14,083	22,894
Loss from operations	(6,559)	(11,335)	(14,083)	(22,894)
Other income (expense):
Interest income (expense), net	(103)	78	(157)	229
Other expense, net	(314)	(16)	(321)	(27)
Other income (expense), net	(417)	62	(478)	202
Net loss	$ (6,976)	$ (11,273)	$ (14,561)	$ (22,692)
Net loss per share attributable to common stockholders—basic and diluted	$ (0.26)	$ (0.54)	$ (0.56)	$ (1.09)
Weighted-average common shares outstanding—basic and diluted	26,878,962	20,903,298	25,808,043	20,859,251
Net loss	$ (6,976)	$ (11,273)	$ (14,561)	$ (22,692)
Comprehensive loss	$ (6,976)	$ (11,273)	$ (14,561)	$ (22,692)

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Stockholders' Equity (unaudited) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Deficit
Balance at Dec. 31, 2018	$ 49,456	$ 21	$ 167,040	$ (117,605)
Balance, Shares at Dec. 31, 2018		20,809,025
Issuance of common stock, net of issuance costs	9,446	$ 2	9,444
Issuance of common stock, net of issuance costs, shares		2,632,092
Exercise of common stock options	13		13
Exercise of common stock options, shares		7,039
Issuance of common stock through employee stock purchase plan ("ESPP")	49		49
Issuance of common stock through employee stock purchase plan ("ESPP"), shares		14,009
Stock-based compensation	1,401		1,401
Net loss	(22,692)			(22,692)
Balance at Jun. 30, 2019	37,673	$ 23	177,947	(140,297)
Balance, Shares at Jun. 30, 2019		23,462,165
Balance at Mar. 31, 2019	38,679	$ 21	167,682	(129,024)
Balance, Shares at Mar. 31, 2019		20,816,064
Issuance of common stock, net of issuance costs	9,446	$ 2	9,444
Issuance of common stock, net of issuance costs, shares		2,632,092
Issuance of common stock through employee stock purchase plan ("ESPP")	49		49
Issuance of common stock through employee stock purchase plan ("ESPP"), shares		14,009
Stock-based compensation	772		772
Net loss	(11,273)			(11,273)
Balance at Jun. 30, 2019	37,673	$ 23	177,947	(140,297)
Balance, Shares at Jun. 30, 2019		23,462,165
Balance at Dec. 31, 2019	$ 17,198	$ 25	182,117	(164,944)
Balance, Shares at Dec. 31, 2019	24,735,009	24,735,009
Issuance of common stock, net of issuance costs	$ 13,658	$ 7	13,651
Issuance of common stock, net of issuance costs, shares		7,317,074
Exercise of common stock options	18		18
Exercise of common stock options, shares		11,928
Issuance of common stock through employee stock purchase plan ("ESPP")	27		27
Issuance of common stock through employee stock purchase plan ("ESPP"), shares		20,003
Issuance of common stock through release of restricted stock units ("RSUs"), shares		140,720
Stock-based compensation	2,033		2,033
Net loss	(14,561)			(14,561)
Balance at Jun. 30, 2020	$ 18,373	$ 32	197,846	(179,505)
Balance, Shares at Jun. 30, 2020	32,224,734	32,224,734
Balance at Mar. 31, 2020	$ 10,658	$ 25	183,162	(172,529)
Balance, Shares at Mar. 31, 2020		24,742,146
Issuance of common stock, net of issuance costs	13,658	$ 7	13,651
Issuance of common stock, net of issuance costs, shares		7,317,074
Exercise of common stock options	8		8
Exercise of common stock options, shares		4,791
Issuance of common stock through employee stock purchase plan ("ESPP")	27		27
Issuance of common stock through employee stock purchase plan ("ESPP"), shares		20,003
Issuance of common stock through release of restricted stock units ("RSUs"), shares		140,720
Stock-based compensation	998		998
Net loss	(6,976)			(6,976)
Balance at Jun. 30, 2020	$ 18,373	$ 32	$ 197,846	$ (179,505)
Balance, Shares at Jun. 30, 2020	32,224,734	32,224,734

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Cash Flows (unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Cash flows from operating activities:
Net loss	$ (14,561)	$ (22,692)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	2,033	1,401
Depreciation expense	83	79
Non-cash interest expense	4	4
Non-cash lease expense	268	246
Changes in assets and liabilities:
Prepaid expenses and other current assets	1,105	(900)
Other assets		123
Accounts payable	(2,483)	216
Accrued expenses	(1,506)	(868)
Operating lease liabilities	(226)	(244)
Other liabilities		(1)
Net cash used in operating activities	(15,283)	(22,636)
Cash flows from investing activities:
Purchases of property and equipment		(101)
Net cash used in investing activities		(101)
Cash flows from financing activities:
Proceeds from the issuance of common stock, net of issuance costs	13,700	9,569
Proceeds from exercise of stock options	18	13
Proceeds from the issuance of stock through ESPP	27	49
Repayment of loan payable	(2,000)
Other	(16)	(14)
Net cash provided by financing activities	11,729	9,617
Net decrease in cash and cash equivalents	(3,554)	(13,120)
Cash and cash equivalents, beginning of period	30,007	61,643
Cash and cash equivalents, end of period	26,453	48,523
Supplemental disclosures:
Right-of-use assets obtained in exchange of operating lease obligations		992
Issuance costs included in accounts payable and accrued expenses	$ 42	$ 123

Nature of Business

Nature of Business	6 Months Ended
	Jun. 30, 2020
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Nature of Business	1. Nature of Business Allena Pharmaceuticals, Inc. (the “Company”) is a late-stage clinical biopharmaceutical company dedicated to developing and commercializing first-in-class, oral enzyme therapeutics to treat patients with rare and severe metabolic and kidney disorders. The Company is focused on metabolic disorders that result in excess accumulation of certain metabolites that can cause kidney stones, damage the kidney, and potentially lead to chronic kidney disease (“CKD”) and end-stage renal disease. The Company’s lead product candidate, reloxaliase (formerly known as ALLN-177), is a first-in-class, oral enzyme therapeutic that it is developing for the treatment of hyperoxaluria, a metabolic disorder commonly associated with kidney stones, CKD and other serious kidney diseases. The Company was incorporated under the laws of the State of Delaware on June 24, 2011 and is located in Newton, Massachusetts. On June 5, 2020, the Company completed a registered direct offering, in which the Company issued and sold 7,317,074 shares of its common stock, at a purchase price of $2.05 per share, for gross proceeds of $15.0 million through a securities purchase agreement with certain institutional and accredited investors. The shares of common stock sold in this offering were being offered by the Company pursuant to an effective shelf registration statement on Form S-3, which was originally filed with the Securities and Exchange Commission (the “SEC”) on December 3, 2018, as amended, and was declared effective on December 26, 2018 (File No. 333-228656) and a prospectus supplement thereunder filed on June 5, 2020. As a result of the registered direct offering, the Company received approximately $13.7 million after deducting offering costs. On July 30, 2020, the Company completed a public underwritten offering of 5,894,191 shares of its common stock, including the exercise in full of the underwriter’s option to purchase an additional 768,807 shares of common stock, at a price to the public of $1.30 per share, for gross proceeds of $7.7 million , before deducting underwriting discounts and commissions and offering expenses. As a result of this public offering, the Company received approximately $6.7 million after deducting offering costs. The Company is subject to risks common to companies in the biotechnology industry, including but not limited to, risks of failure of preclinical studies and clinical trials, the need to obtain marketing approval for any drug product candidate that it may identify and develop, the need to successfully commercialize and gain market acceptance of its product candidates, dependence on key personnel, protection of proprietary technology, compliance with government regulations, development by competitors of technological innovations, reliance on third party manufacturers, ability to transition from pilot-scale manufacturing to large-scale production of products and the need to obtain adequate additional financing to fund the development of its product candidates. Liquidity and Going Concern The Company had an accumulated deficit of $179.5 million at June 30, 2020 and will require substantial additional capital to fund operations. The future success of the Company is dependent on its ability to identify and develop its product candidates and ultimately upon its ability to attain profitable operations. At June 30, 2020, the Company had $26.5 million of cash and cash equivalents. The Company’s available cash and cash equivalents as of June 30, 2020 The Company requires additional capital to sustain its operations, including its reloxaliase development program. The failure to obtain sufficient funds when needed would have a material adverse effect on the Company’s business, results of operations and financial condition and jeopardize its ability to continue operations. , which may include amending, delaying, limiting, reducing, or terminating one or more of its ongoing or planned clinical trials or development programs of its product candidates.

Summary of Significant Accounti

Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2020
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Basis of Presentation The Company’s unaudited interim condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States (“U.S. GAAP”). Any reference in these notes to applicable guidance is meant to refer to the authoritative United States generally accepted accounting principles as found in the Accounting Standards Codification (“ASC”) and Accounting Standards Updates (ASU) of the Financial Accounting Standards Board (“FASB”). Certain information and footnote disclosures normally included in financial statements prepared in accordance with U.S. GAAP have been condensed or omitted from this report, as is permitted by such rules and regulations. Accordingly, these financial statements should be read in conjunction with the audited financial statements as of and for the year ended December 31, 2019 and notes thereto, included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2019 filed with the SEC on March 16, 2020. The unaudited interim consolidated financial statements have been prepared on the same basis as the audited financial statements. In the opinion of the Company’s management, the accompanying unaudited interim condensed consolidated financial statements contain all adjustments which are necessary to present fairly the Company’s financial position as of June 30, 2020, the results of its operations for the three and six months ended June 30, 2020 and June 30, 2019 and cash flows for the six months ended June 30, 2020 and June 30, 2019. Such adjustments are of a normal and recurring nature. The results for the three months ended June 30, 2020 are not necessarily indicative of the results for the year ending December 31, 2020, or for any future period. Principles of Consolidation The consolidated financial statements include the accounts of Allena Pharmaceuticals, Inc. and its wholly owned subsidiaries Allena Pharmaceuticals Security Corporation (“Security Corporation”), which was incorporated in December 2014, and Allena Pharmaceuticals Ireland Limited, which was incorporated in March 2017. All intercompany transactions and balances have been eliminated. Fair Value of Financial Instruments Fair value is defined as the price that would be received upon sale of an asset or paid to transfer a liability between market participants at measurement dates. ASC Topic 820, Fair Value Measurement Level 1 inputs: Quoted prices in active markets for identical assets or liabilities. Level 2 inputs: Inputs other than quoted prices included within Level 1 that are either directly or indirectly observable, such as quoted market prices, interest rates and yield curves. Level 3 inputs: Unobservable inputs developed using estimates or assumptions developed by the Company, which reflect those that a market participant would use in pricing the asset or liability. To the extent that the valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair value requires more judgment. Accordingly, the degree of judgment exercised by the Company in determining fair value is greatest for instruments categorized in Level 3. A financial instrument’s level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement. Use of Estimates The preparation of the Company’s condensed consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, expenses and related disclosure of contingent assets and liabilities at the date of the financial statements and reported amounts of expenses during the reporting period. On an ongoing basis, the Company’s management evaluates its estimates, which include but are not limited to management’s judgement of prepaid and accrued research and development expenses, and the valuation of share-based awards. Actual results could differ from those estimates. The remainder of the Company’s significant accounting policies are described in the Annual Report filed on Form 10-K for the year ended December 31, 2019 that was filed with the United States Securities and Exchange Commission on March 16, 2020. Recently Adopted Accounting Pronouncements In 2018, the FASB issued ASU 2018-13, Fair Value Measurement (Topic 820): Disclosure Framework-Changes to the Disclosure Requirements for Fair Value Measurement In 2018, the FASB issued ASU 2018-15, Intangibles—Goodwill and Other—Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract Recently Issued Accounting Pronouncements In 2016, the FASB issued ASU 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments In December 2019, the FASB issued ASU No. 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes

Net Loss per Share

Net Loss per Share	6 Months Ended
	Jun. 30, 2020
Earnings Per Share [Abstract]
Net Loss per Share	3. Net Loss per Share Basic net loss per share is calculated by dividing the net loss attributable to common stockholders by the weighted-average number of common shares outstanding for the period, without consideration for potentially dilutive securities. The Company has computed diluted net loss per common share after giving consideration to all potentially dilutive common shares, including options to purchase common stock, restricted stock units and warrants to purchase common stock, outstanding during the period determined using the treasury-stock and if-converted methods, except where the effect of including such securities would be antidilutive. Because the Company has reported net losses since inception, these potential common shares have been anti-dilutive and basic and diluted loss per share have been the same. Basic and diluted net loss per share attributable to common stockholders was calculated as follows (in thousands, except share and per share data): Three Months Ended June 30, Six Months Ended June 30, 2020 2019 2020 2019 Numerator: Net loss $ (6,976 ) $ (11,273 ) $ (14,561 ) $ (22,692 ) Net loss attributable to common stockholders $ (6,976 ) $ (11,273 ) $ (14,561 ) $ (22,692 ) Denominator: Weighted-average common shares—basic and diluted 26,878,962 20,903,298 25,808,043 20,859,251 Net loss per share attributable to common stockholders—basic and diluted $ (0.26 ) $ (0.54 ) $ (0.56 ) $ (1.09 ) The following table sets forth the potentially dilutive securities that have been excluded from the calculation of diluted net loss per share because to include them would be anti-dilutive (in common stock equivalent shares): Six Months Ended June 30, 2020 2019 Warrants 9,040 9,040 Stock options 3,766,567 3,142,132 Restricted stock units 553,468 — Total 4,329,075 3,151,172

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Jun. 30, 2020
Fair Value Disclosures [Abstract]
Fair Value Measurements	4. Fair Value Measurements The following tables present information about the Company’s financial assets and liabilities that have been measured at fair value at June 30, 2020 and December 31, 2019, and indicates the fair value hierarchy of the valuation inputs utilized to determine such fair value (in thousands): Description June 30, 2020 Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Assets: Money market funds, included in cash and cash equivalents $ 26,119 $ 26,119 $ — $ — Total assets $ 26,119 $ 26,119 $ — $ — Description December 31, 2019 Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Assets: Money market funds, included in cash and cash equivalents $ 29,592 $ 29,592 $ — $ — Total assets $ 29,592 $ 29,592 $ — $ — At June 30, 2020 and December 31, 2019, all of the Company’s cash equivalents were comprised of money market funds. There were no changes to the valuation methods during the three and six months ended June 30, 2020 and the year ended December 31, 2019. There were no transfers within the fair value hierarchy during the three and six months ended June 30, 2020 and the year ended December 31, 2019. The carrying amounts reflected in the consolidated balance sheets for cash and cash equivalents, prepaid expenses and other current assets, accounts payable and accrued expenses approximate their carrying values. The Company believes the terms of the loan payable reflect current market conditions for an instrument with similar terms and maturity, therefore the carrying value of the Company’s debt approximates its fair value based on Level 3 of the fair value hierarchy.

Accrued Expenses

Accrued Expenses	6 Months Ended
	Jun. 30, 2020
Payables And Accruals [Abstract]
Accrued Expenses	5. Accrued Expenses Accrued expenses consist of the following (in thousands): June 30, 2020 December 31, 2019 Payroll and employee-related expenses $ 1,392 $ 1,250 Third-party research and development expenses 267 1,393 Professional fees 179 229 Restructuring charges — 373 Loan interest 33 43 Other 14 82 Total accrued expenses $ 1,885 $ 3,370

Restructuring Charges

Restructuring Charges	6 Months Ended
	Jun. 30, 2020
Restructuring And Related Activities [Abstract]
Restructuring Charges	6. Restructuring Charges On November 29, 2019, following the completion of a strategic review of its business, the Company's Board of Directors approved a workforce reduction plan, or the Workforce Reduction, to reduce its workforce headcount by approximately 38%. The Company evaluated the related employee severance and other benefits to employees in connection with the Workforce Reduction to determine whether the benefits were within the scope ASC 712, Compensation - Non-retirement Post-employment Benefits Exit or Disposal Cost Obligations, Activity related to the Company’s accrued restructuring charges during the six months ended June 30, 2020 is as follows: Accrued restructuring charges at December 31, 2019 $ 373 Amounts paid through June 30, 2020 (373 ) Accrued restructuring charges at June 30, 2020 $ —

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2020
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	7. Commitments and Contingencies The Company is a party to operating leases for approximately 7,795 square feet of office space in Newton, MA (Newton Lease), and for approximately 7,564 square feet of laboratory and office space in Sudbury, MA (Sudbury Lease). The Newton Lease expires on December 31, 2020 and the Sudbury Lease expires on February 28, 2021. Annualized base rent for the Newton Lease and the Sudbury lease is approximately $0.3 million and $0.2 million, respectively. Minimum payments of the Company’s operating lease liabilities in accordance with ASC 842 as of June 30, 2020 are as follows (in thousands): Remainder of 2020 $ 273 2021 30 Total maturities 303 Less: Amount representing interest (7 ) Present value of operating lease liabilities $ 296 Lease costs included in the Company’s condensed consolidated statements of operations and comprehensive loss for each of the three and six months ended June 30, 2020 and 2019 was $0.1 million and $0.3 million, respectively. The Company’s operating leases had a weighted average remaining lease term of 0.6 years and a weighted average discount rate of 5.5% at June 30, 2020.

Loan and Security Agreement

Loan and Security Agreement	6 Months Ended
	Jun. 30, 2020
Debt Disclosure [Abstract]
Loan and Security Agreement	8. Loan and Security Agreement On June 29, 2018 the Company entered into a loan agreement with Pacific Western Bank (“PWB Loan Agreement”) providing up to $12.0 million of borrowings, of which $10.0 million was advanced on June 29, 2018. The remaining $2.0 million of borrowings available under the PWB Loan Agreement were available to the Company through one additional advance request until December 31, 2019. Borrowings are secured by a lien on all Company assets, excluding intellectual property, and amounts borrowed have a floating per annum interest rate of the greater of 5.0% or the prime rate. The PWB Loan Agreement has a term of 48 months and an interest only period of 18 months. Upon the expiration of the interest only period on December 31, 2019, amounts borrowed will be repaid over 30 equal monthly payments of principal plus accrued but unpaid interest. At its option, the Company may prepay all, but not less than all, of the outstanding borrowings subject to a prepayment premium as defined in the Loan Agreement. Upon the closing of one or more financings, in which the Company receives aggregate gross proceeds of at least $25 million, a success fee of $300,000 will be due and payable to PWB. As a result of the gross proceeds of $15.0 million received from the registered direct offering completed on June 5, 2020, combined with $10.0 million of gross proceeds received from the registered direct offering completed in June 2019, and $2.7 million of gross proceeds received through the At-the-Market offering completed in December 2019, the conditions required to trigger the success fee were fulfilled and the success fee was paid to PWB at the time of the closing of the registered direct offering. The success fee was recorded as other expense on the Company’s condensed consolidated statements of operations and comprehensive loss at the time the registered direct offering was completed. The PWB Loan Agreement contains negative covenants restricting the Company’s activities, including limitations on dispositions, mergers or acquisitions, incurring indebtedness or liens, paying dividends or making investments and certain other business transactions. There are no financial covenants associated with the PWB Loan Agreement. The obligations under the PWB Loan Agreement are subject to acceleration upon the occurrence of specified events of default, including a material adverse change in the Company’s business, operations or financial or other condition. The Company has determined that the risk of subjective acceleration under the material adverse events clause is remote and therefore has classified the outstanding principal based on scheduled principal payments. The Company evaluated the PWB Loan Agreement for embedded features that require bifurcation, noting certain features were required to be bifurcated, but were concluded to be de minimis in value at June 30, 2020 and December 31, 2019.

Stockholders' Deficit

Stockholders' Deficit	6 Months Ended
	Jun. 30, 2020
Equity [Abstract]
Stockholders' Deficit	9. Stockholders’ Deficit Common Stock The holders of common stock are entitled to one vote for each share held. Common stockholders are not entitled to receive dividends, unless declared by the Board of Directors. The Company has reserved for future issuances the following shares of common stock as of June 30, 2020 and December 31, 2019: June 30, 2020 December 31, 2019 Warrants 9,040 9,040 Stock options and restricted stock units 5,907,055 5,070,303 Employee stock purchase plan 360,002 380,005 Total 6,276,097 5,459,348

Stock Incentive Plan

Stock Incentive Plan	6 Months Ended
	Jun. 30, 2020
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock Incentive Plan	10. Stock Incentive Plan On October 31, 2017, the Company adopted the 2017 Stock Option and Incentive Plan (“2017 Plan”). Upon the adoption of the 2017 Plan, no further grants would be made under the 2011 Stock Incentive Plan (“2011 Plan”). The 2017 Plan initially provided for the grant of awards for 2,038,021 shares of common stock. In addition to the shares available for grant under the 2017 Plan, any awards outstanding under the 2011 Plan as of the October 31, 2017 are cancelled, forfeited or otherwise terminated without being exercised, the number of shares underlying such awards will be available for future grant under the 2017 Plan. The 2017 Plan also provides that an additional number of shares will automatically be added to the shares authorized for issuance under the 2017 Plan on January 1 of each year. The number of shares added each year will be equal to the lesser of: (i) 4% of the outstanding shares on the immediately preceding December 31 or (ii) such amount as determined by the Compensation Committee of the registrant’s Board of Directors. All of the Company’s employees, officers, directors, consultants and advisors are eligible to be granted options, restricted stock units (“RSUs”), and other share-based awards under the terms of the 2017 Plan. As of June 30, 2020, 1,587,020 shares of common stock were available for future grant under the 2017 Plan. All stock option grants are nonstatutory stock options except option grants to employees (including officers and directors) intended to qualify as incentive stock options under the Internal Revenue Code of 1986, as amended. Incentive stock options may not be granted at less than the fair market value of the Company’s common stock on the date of grant, as determined in good faith by the Board of Directors at its sole discretion. Nonqualified stock options may be granted at an exercise price established by the Board of Directors at its sole discretion (which has not been less than fair market value on the date of grant) and the vesting periods may vary. Vesting periods are generally four years and are determined by the Board of Directors or a delegated subcommittee. Stock options become exercisable as they vest. Options granted under both the 2011 Plan and 2017 Plan expire no more than 10 years from the date of grant. Stock-based compensation expense included in the Company’s statements of operations and comprehensive loss is as follows (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2020 2019 2020 2019 Research and development $ 281 $ 311 $ 709 $ 566 General and administrative 717 461 1,324 835 Total $ 998 $ 772 $ 2,033 $ 1,401 The fair value of each stock option granted to employees and directors during the three and six months ended June 30, 2019 was estimated on the date of grant using the Black-Scholes option-pricing model, with the following range of assumptions as follows: Three Months Ended June 30, 2019 Six Months Ended June 30, 2019 Risk-free interest rate 1.9%-2.3% 1.9%-2.6% Expected dividend yield —% —% Expected term (in years) 5.5-6.1 5.5-6.8 Expected volatility 82%-83% 82%-83% The Company did not grant any stock options during the three and six months ended June 30, 2020. A summary of the stock option activity under the 2011 and 2017 Plans is as follows: Shares Weighted- Average Exercise Price Weighted- Average Remaining Contractual Life (in years) Aggregate Intrinsic Value (in thousands) Outstanding at December 31, 2019 3,915,591 $ 4.33 8.1 $ 1,921 Granted — — Exercised (11,928 ) 1.42 Cancelled (137,096 ) 6.15 Outstanding at June 30, 2020 3,766,567 $ 4.27 7.5 $ 299 Exercisable at June 30, 2020 2,134,395 $ 3.85 6.6 $ 299 As of June 30, 2020, total unrecognized stock-based compensation expense relating to unvested stock options was $5.3 million. This amount is expected to be recognized over a weighted-average period of 2.4 years. Restricted Stock Units (RSUs) In December 2019, the Company awarded 517,750 time-based RSUs to certain employees and officers of the Company. In May 2020, the Company awarded 206,377 additional time-based RSUs to officers of the Company. The RSUs awarded to employees vest as to 50% on June 2, 2020 and 50% on December 2, 2020. The RSUs awarded to officers vest as to 100% on December 2, 2020. The RSUs are generally forfeited if the employment relationship terminates with the Company prior to vesting. For the three and six months ended June 30, 2020, the Company recognized $0.3 million and $0.7 million of stock-based compensation expense, respectively, related to these awards. As of June 30, 2020, the total remaining unrecognized compensation cost related to all nonvested RSUs amounted to $0.8 million, which is expected to be recognized during the remainder of 2020. Shares Weighted-Average Grant Date Fair Value Nonvested at December 31, 2019 517,750 $ 2.42 Granted 206,377 1.71 Vested (140,720 ) 2.42 Forfeited (29,939 ) 2.42 Nonvested at June 30, 2020 553,468 $ 2.16

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2020
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The Company’s unaudited interim condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States (“U.S. GAAP”). Any reference in these notes to applicable guidance is meant to refer to the authoritative United States generally accepted accounting principles as found in the Accounting Standards Codification (“ASC”) and Accounting Standards Updates (ASU) of the Financial Accounting Standards Board (“FASB”). Certain information and footnote disclosures normally included in financial statements prepared in accordance with U.S. GAAP have been condensed or omitted from this report, as is permitted by such rules and regulations. Accordingly, these financial statements should be read in conjunction with the audited financial statements as of and for the year ended December 31, 2019 and notes thereto, included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2019 filed with the SEC on March 16, 2020. The unaudited interim consolidated financial statements have been prepared on the same basis as the audited financial statements. In the opinion of the Company’s management, the accompanying unaudited interim condensed consolidated financial statements contain all adjustments which are necessary to present fairly the Company’s financial position as of June 30, 2020, the results of its operations for the three and six months ended June 30, 2020 and June 30, 2019 and cash flows for the six months ended June 30, 2020 and June 30, 2019. Such adjustments are of a normal and recurring nature. The results for the three months ended June 30, 2020 are not necessarily indicative of the results for the year ending December 31, 2020, or for any future period.
Principles of Consolidation	Principles of Consolidation The consolidated financial statements include the accounts of Allena Pharmaceuticals, Inc. and its wholly owned subsidiaries Allena Pharmaceuticals Security Corporation (“Security Corporation”), which was incorporated in December 2014, and Allena Pharmaceuticals Ireland Limited, which was incorporated in March 2017. All intercompany transactions and balances have been eliminated.
Fair Value of Financial Instruments	Fair Value of Financial Instruments Fair value is defined as the price that would be received upon sale of an asset or paid to transfer a liability between market participants at measurement dates. ASC Topic 820, Fair Value Measurement Level 1 inputs: Quoted prices in active markets for identical assets or liabilities. Level 2 inputs: Inputs other than quoted prices included within Level 1 that are either directly or indirectly observable, such as quoted market prices, interest rates and yield curves. Level 3 inputs: Unobservable inputs developed using estimates or assumptions developed by the Company, which reflect those that a market participant would use in pricing the asset or liability. To the extent that the valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair value requires more judgment. Accordingly, the degree of judgment exercised by the Company in determining fair value is greatest for instruments categorized in Level 3. A financial instrument’s level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement.
Use of Estimates	Use of Estimates The preparation of the Company’s condensed consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, expenses and related disclosure of contingent assets and liabilities at the date of the financial statements and reported amounts of expenses during the reporting period. On an ongoing basis, the Company’s management evaluates its estimates, which include but are not limited to management’s judgement of prepaid and accrued research and development expenses, and the valuation of share-based awards. Actual results could differ from those estimates. The remainder of the Company’s significant accounting policies are described in the Annual Report filed on Form 10-K for the year ended December 31, 2019 that was filed with the United States Securities and Exchange Commission on March 16, 2020.
Recently Adopted Accounting Pronouncements	Recently Adopted Accounting Pronouncements In 2018, the FASB issued ASU 2018-13, Fair Value Measurement (Topic 820): Disclosure Framework-Changes to the Disclosure Requirements for Fair Value Measurement In 2018, the FASB issued ASU 2018-15, Intangibles—Goodwill and Other—Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract
Recently Issued Accounting Pronouncements	Recently Issued Accounting Pronouncements In 2016, the FASB issued ASU 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments In December 2019, the FASB issued ASU No. 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes

Net Loss per Share (Tables)

Net Loss per Share (Tables)	6 Months Ended
	Jun. 30, 2020
Earnings Per Share [Abstract]
Summary of Basic and Diluted Net Loss per Share Attributable to Common Stockholders	Basic and diluted net loss per share attributable to common stockholders was calculated as follows (in thousands, except share and per share data): Three Months Ended June 30, Six Months Ended June 30, 2020 2019 2020 2019 Numerator: Net loss $ (6,976 ) $ (11,273 ) $ (14,561 ) $ (22,692 ) Net loss attributable to common stockholders $ (6,976 ) $ (11,273 ) $ (14,561 ) $ (22,692 ) Denominator: Weighted-average common shares—basic and diluted 26,878,962 20,903,298 25,808,043 20,859,251 Net loss per share attributable to common stockholders—basic and diluted $ (0.26 ) $ (0.54 ) $ (0.56 ) $ (1.09 )
Summary of Anti-dilutive Securities Excluded from Calculation of Diluted Net Loss per Share	The following table sets forth the potentially dilutive securities that have been excluded from the calculation of diluted net loss per share because to include them would be anti-dilutive (in common stock equivalent shares): Six Months Ended June 30, 2020 2019 Warrants 9,040 9,040 Stock options 3,766,567 3,142,132 Restricted stock units 553,468 — Total 4,329,075 3,151,172

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jun. 30, 2020
Fair Value Disclosures [Abstract]
Summary of Financial Assets and Liabilities Measured at Fair Value	The following tables present information about the Company’s financial assets and liabilities that have been measured at fair value at June 30, 2020 and December 31, 2019, and indicates the fair value hierarchy of the valuation inputs utilized to determine such fair value (in thousands): Description June 30, 2020 Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Assets: Money market funds, included in cash and cash equivalents $ 26,119 $ 26,119 $ — $ — Total assets $ 26,119 $ 26,119 $ — $ — Description December 31, 2019 Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Assets: Money market funds, included in cash and cash equivalents $ 29,592 $ 29,592 $ — $ — Total assets $ 29,592 $ 29,592 $ — $ —

Accrued Expenses (Tables)

Accrued Expenses (Tables)	6 Months Ended
	Jun. 30, 2020
Payables And Accruals [Abstract]
Schedule of Accrued Expenses	Accrued expenses consist of the following (in thousands): June 30, 2020 December 31, 2019 Payroll and employee-related expenses $ 1,392 $ 1,250 Third-party research and development expenses 267 1,393 Professional fees 179 229 Restructuring charges — 373 Loan interest 33 43 Other 14 82 Total accrued expenses $ 1,885 $ 3,370

Restructuring Charges (Tables)

Restructuring Charges (Tables)	6 Months Ended
	Jun. 30, 2020
Restructuring And Related Activities [Abstract]
Schedule of Activity Related to Accrued Restructuring Charges	Activity related to the Company’s accrued restructuring charges during the six months ended June 30, 2020 is as follows: Accrued restructuring charges at December 31, 2019 $ 373 Amounts paid through June 30, 2020 (373 ) Accrued restructuring charges at June 30, 2020 $ —

Commitments and Contingencies (

Commitments and Contingencies (Tables)	6 Months Ended
	Jun. 30, 2020
ASC 842
Operating Leased Assets [Line Items]
Schedule of Minimum Payments of Operating Lease Liabilities	Minimum payments of the Company’s operating lease liabilities in accordance with ASC 842 as of June 30, 2020 are as follows (in thousands): Remainder of 2020 $ 273 2021 30 Total maturities 303 Less: Amount representing interest (7 ) Present value of operating lease liabilities $ 296

Stockholders' Deficit (Tables)

Stockholders' Deficit (Tables)	6 Months Ended
	Jun. 30, 2020
Equity [Abstract]
Summary of Shares of Common Stock Reserved	The Company has reserved for future issuances the following shares of common stock as of June 30, 2020 and December 31, 2019: June 30, 2020 December 31, 2019 Warrants 9,040 9,040 Stock options and restricted stock units 5,907,055 5,070,303 Employee stock purchase plan 360,002 380,005 Total 6,276,097 5,459,348

Stock Incentive Plan (Tables)

Stock Incentive Plan (Tables)	6 Months Ended
	Jun. 30, 2020
Summary of Stock-based Compensation Expense	Stock-based compensation expense included in the Company’s statements of operations and comprehensive loss is as follows (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2020 2019 2020 2019 Research and development $ 281 $ 311 $ 709 $ 566 General and administrative 717 461 1,324 835 Total $ 998 $ 772 $ 2,033 $ 1,401
Summary of Stock Option Activity	The Company did not grant any stock options during the three and six months ended June 30, 2020. A summary of the stock option activity under the 2011 and 2017 Plans is as follows: Shares Weighted- Average Exercise Price Weighted- Average Remaining Contractual Life (in years) Aggregate Intrinsic Value (in thousands) Outstanding at December 31, 2019 3,915,591 $ 4.33 8.1 $ 1,921 Granted — — Exercised (11,928 ) 1.42 Cancelled (137,096 ) 6.15 Outstanding at June 30, 2020 3,766,567 $ 4.27 7.5 $ 299 Exercisable at June 30, 2020 2,134,395 $ 3.85 6.6 $ 299
Restricted Stock Units (RSUs)
Summary of Nonvested RSUs	Shares Weighted-Average Grant Date Fair Value Nonvested at December 31, 2019 517,750 $ 2.42 Granted 206,377 1.71 Vested (140,720 ) 2.42 Forfeited (29,939 ) 2.42 Nonvested at June 30, 2020 553,468 $ 2.16
Employees and Directors
Schedule of Assumptions Used in Black-Scholes Option Pricing Model to Estimate Fair Value of Stock Options	The fair value of each stock option granted to employees and directors during the three and six months ended June 30, 2019 was estimated on the date of grant using the Black-Scholes option-pricing model, with the following range of assumptions as follows: Three Months Ended June 30, 2019 Six Months Ended June 30, 2019 Risk-free interest rate 1.9%-2.3% 1.9%-2.6% Expected dividend yield —% —% Expected term (in years) 5.5-6.1 5.5-6.8 Expected volatility 82%-83% 82%-83%

Nature of Business - Additional

Nature of Business - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	Jul. 30, 2020	Jun. 05, 2020	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Class of Stock [Line Items]
Proceeds from the issuance of common stock, net of issuance costs			$ 13,700	$ 9,569
Accumulated deficit			179,505		$ 164,944
Cash and cash equivalents			$ 26,453		$ 30,007
Direct Offering
Class of Stock [Line Items]
Issuance of common stock, net of issuance costs, shares		7,317,074
Issuance price per share		$ 2.05
Gross proceeds from issuance of common stock		$ 15,000
Proceeds from the issuance of common stock, net of issuance costs		$ 13,700
Public Underwritten Offering | Subsequent Event
Class of Stock [Line Items]
Issuance of common stock, net of issuance costs, shares	5,894,191
Issuance price per share	$ 1.30
Gross proceeds from issuance of common stock	$ 7,700
Proceeds from the issuance of common stock, net of issuance costs	$ 6,700
Over-allotment Option | Subsequent Event
Class of Stock [Line Items]
Issuance of common stock, net of issuance costs, shares	768,807

Summary of Significant Accoun_3

Summary of Significant Accounting Policies - Additional Information (Details)	6 Months Ended
	Jun. 30, 2020
Summary Of Significant Accounting Policies [Line Items]
Entity incorporated date	Dec. 31, 2014
Allena Pharmaceuticals Security Corporation
Summary Of Significant Accounting Policies [Line Items]
Entity incorporated date	Dec. 31, 2014
Allena Pharmaceuticals Ireland Limited
Summary Of Significant Accounting Policies [Line Items]
Entity incorporated date	Mar. 31, 2017

Net Loss per Share - Summary of

Net Loss per Share - Summary of Basic and Diluted Net Loss per Share Attributable to Common Stockholders (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Numerator:
Net loss	$ (6,976)	$ (11,273)	$ (14,561)	$ (22,692)
Net loss attributable to common stockholders	$ (6,976)	$ (11,273)	$ (14,561)	$ (22,692)
Denominator:
Weighted-average common shares—basic and diluted	26,878,962	20,903,298	25,808,043	20,859,251
Net loss per share attributable to common stockholders—basic and diluted	$ (0.26)	$ (0.54)	$ (0.56)	$ (1.09)

Net Loss per Share - Summary _2

Net Loss per Share - Summary of Anti-dilutive Securities Excluded from Calculation of Diluted Net Loss per Share (Details) - shares	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from the calculation of loss per share	4,329,075	3,151,172
Restricted Stock Units
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from the calculation of loss per share	553,468
Warrants
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from the calculation of loss per share	9,040	9,040
Stock Options
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from the calculation of loss per share	3,766,567	3,142,132

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Financial Assets and Liabilities Measured at Fair Value (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets	$ 26,119	$ 29,592
Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets	26,119	29,592
Money market funds, included in cash and cash equivalents
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Money market funds, included in cash and cash equivalents	26,119	29,592
Money market funds, included in cash and cash equivalents | Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Money market funds, included in cash and cash equivalents	$ 26,119	$ 29,592

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Details) - USD ($)	3 Months Ended	6 Months Ended	12 Months Ended
	Jun. 30, 2020	Jun. 30, 2020	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Change in valuation methods or transfers	$ 0	$ 0	$ 0
Transfers within fair value hierarchy	$ 0	$ 0	$ 0

Accrued Expenses - Schedule of

Accrued Expenses - Schedule of Accrued Expenses (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Payables And Accruals [Abstract]
Payroll and employee-related expenses	$ 1,392	$ 1,250
Third-party research and development expenses	267	1,393
Professional fees	179	229
Restructuring charges		373
Loan interest	33	43
Other	14	82
Total accrued expenses	$ 1,885	$ 3,370

Restructuring Charges - Additio

Restructuring Charges - Additional Information (Details) $ in Millions	Nov. 29, 2019USD ($)
Restructuring And Related Activities [Abstract]
Restructuring charges, number of workforce headcount reduction percentage	38.00%
Restructuring expense at the time of workforce reduction	$ 0.6

Restructuring Charges - Schedul

Restructuring Charges - Schedule of Activity Related to Accrued Restructuring Charges (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2020USD ($)
Restructuring And Related Activities [Abstract]
Accrued restructuring charges at December 31, 2019	$ 373
Amounts paid through June 30, 2020	$ (373)

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020USD ($)	Jun. 30, 2019USD ($)	Jun. 30, 2020USD ($)ft²	Jun. 30, 2019USD ($)
Operating Leased Assets [Line Items]
Lease costs	$ 0.1	$ 0.3	$ 0.1	$ 0.3
Operating lease, weighted average remaining lease term	7 months 6 days		7 months 6 days
Operating lease, weighted average discount rate	5.50%		5.50%
Newton, MA
Operating Leased Assets [Line Items]
Rentable office space under operating lease | ft²			7,795
Base rent for office space			$ 0.3
Operating lease expiration date			Dec. 31, 2020
Sudbury, MA
Operating Leased Assets [Line Items]
Rentable office space under operating lease | ft²			7,564
Base rent for office space			$ 0.2
Operating lease expiration date			Feb. 28, 2021

Commitments and Contingencies_2

Commitments and Contingencies - Schedule of Minimum payments of Operating Lease Liabilities (Details) - ASC 842 $ in Thousands	Jun. 30, 2020USD ($)
Lessee Lease Description [Line Items]
Remainder of 2020	$ 273
2021	30
Total maturities	303
Less: Amount representing interest	(7)
Present value of operating lease liabilities	$ 296

Loan and Security Agreement - A

Loan and Security Agreement - Additional Information (Details) - USD ($)	Jun. 05, 2020	Dec. 31, 2019	Jun. 30, 2019	Jun. 29, 2018	Jun. 30, 2020
Direct Offering
Debt Instrument [Line Items]
Gross proceeds from issuance of common stock	$ 15,000,000
Loan Agreement | PWB
Debt Instrument [Line Items]
Loan agreement, maximum borrowing capacity				$ 12,000,000
Loan agreement, advanced amount				10,000,000
Loan agreement, remaining borrowing capacity				$ 2,000,000
Loan agreement, interest rate above prime rate				5.00%
Loan agreement, term				48 months
Loan agreement, interest only payment period				18 months
Expiration of interest only period				Dec. 31, 2019
Loan agreement, number of monthly payments				30 months
Loan agreement, frequency of payments					monthly
Aggregate gross proceeds for success fee to be paid				$ 25,000,000
Success fee payable				$ 300,000
Loan Agreement | PWB | Direct Offering
Debt Instrument [Line Items]
Gross proceeds from issuance of common stock	$ 15,000,000		$ 10,000,000
Loan Agreement | PWB | At-the-Market Offering
Debt Instrument [Line Items]
Gross proceeds from issuance of common stock		$ 2,700,000

Stockholders' Deficit - Additio

Stockholders' Deficit - Additional Information (Details)	6 Months Ended
	Jun. 30, 2020
Equity [Abstract]
Common stock, voting rights	one vote for each share held

Stockholders' Deficit - Summary

Stockholders' Deficit - Summary of Shares of Common Stock Reserved (Details) - shares	Jun. 30, 2020	Dec. 31, 2019
Class of Stock [Line Items]
Shares of common stock reserved for future issuances	6,276,097	5,459,348
Warrants
Class of Stock [Line Items]
Shares of common stock reserved for future issuances	9,040	9,040
Stock Options and Restricted Stock Units
Class of Stock [Line Items]
Shares of common stock reserved for future issuances	5,907,055	5,070,303
Employee Stock Purchase Plan
Class of Stock [Line Items]
Shares of common stock reserved for future issuances	360,002	380,005

Stock Incentive Plan - Addition

Stock Incentive Plan - Additional Information (Details) - USD ($) $ in Thousands	May 31, 2020	Jan. 01, 2020	Jan. 01, 2019	Jan. 01, 2018	Oct. 31, 2017	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of stock options granted						0		0
Expense related to awards granted						$ 998	$ 772	$ 2,033	$ 1,401
Restricted Stock Units (RSUs)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation awards, number of shares employees and officers										517,750
Expense related to awards granted						300		700
Share-based payment arrangement, nonvested award, unrecognized, amount						$ 800		$ 800
Restricted Stock Units (RSUs) | Officer
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation awards, number of shares employees and officers	206,377
Restricted Stock Units (RSUs) | Vesting on June 2, 2020
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation awards, vesting percent								50.00%
Restricted Stock Units (RSUs) | Vesting on December 2, 2020
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation awards, vesting percent								50.00%
Restricted Stock Units (RSUs) | Vesting on December 2, 2020 | Officer
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation awards, vesting percent								100.00%
2011 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares authorized for grant					0
2011 Plan | Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based award, vesting period								4 years
2011 Plan | Stock Options | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based award, expiration period								10 years
2017 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock option grant effective date					Oct. 31, 2017
Share based award, description								Upon the adoption of the 2017 Plan, no further grants would be made under the 2011 Stock Incentive Plan (“2011 Plan”). The 2017 Plan initially provided for the grant of awards for 2,038,021 shares of common stock. In addition to the shares available for grant under the 2017 Plan, any awards outstanding under the 2011 Plan as of the October 31, 2017 are cancelled, forfeited or otherwise terminated without being exercised, the number of shares underlying such awards will be available for future grant under the 2017 Plan. The 2017 Plan also provides that an additional number of shares will automatically be added to the shares authorized for issuance under the 2017 Plan on January 1 of each year. The number of shares added each year will be equal to the lesser of: (i) 4% of the outstanding shares on the immediately preceding December 31 or (ii) such amount as determined by the Compensation Committee of the registrant’s Board of Directors. On January 1, 2018, 2019 and 2020, the shares available for grant under the 2017 Plan was automatically increased by 827,786, 832,361 and 989,400 shares, respectively.
Percentage criteria for additional shares granted					4.00%
Additional shares available for grant		989,400	832,361	827,786
2017 Plan | Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares available for future grant						1,587,020		1,587,020
Stock-based award, vesting period								4 years
2017 Plan | Stock Options | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based award, expiration period								10 years
2017 Plan | Common Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares authorized for grant					2,038,021
2011 And 2017 Plans
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized stock-based compensation expense related to unvested employee stock options						$ 5,300		$ 5,300
Unrecognized stock-based compensation expense, weighted average period for recognition								2 years 4 months 24 days

Stock Incentive Plan - Summary

Stock Incentive Plan - Summary of Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	$ 998	$ 772	$ 2,033	$ 1,401
Research and Development
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	281	311	709	566
General and Administrative
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	$ 717	$ 461	$ 1,324	$ 835

Stock Incentive Plan - Schedule

Stock Incentive Plan - Schedule of Assumptions Used in Black-Scholes Option Pricing Model to Estimate Fair Value of Stock Options (Details) - Stock Options - Employees and Directors	3 Months Ended	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Risk-free interest rate, minimum	1.90%	1.90%
Risk-free interest rate, maximum	2.30%	2.60%
Expected volatility, minimum	82.00%	82.00%
Expected volatility, maximum	83.00%	83.00%
Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (in years)	5 years 6 months	5 years 6 months
Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (in years)	6 years 1 month 6 days	6 years 9 months 18 days

Stock Incentive Plan - Summar_2

Stock Incentive Plan - Summary of Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	6 Months Ended	12 Months Ended
	Jun. 30, 2020	Jun. 30, 2020	Dec. 31, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares, Granted	0	0
2011 And 2017 Plans
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares, Outstanding, Beginning balance		3,915,591
Shares, Exercised		(11,928)
Shares, Cancelled		(137,096)
Shares, Outstanding, Ending balance	3,766,567	3,766,567	3,915,591
Shares, Exercisable	2,134,395	2,134,395
Weighted-Average Exercise Price, Outstanding, Beginning balance		$ 4.33
Weighted-Average Exercise Price, Exercised		1.42
Weighted-Average Exercise Price, Cancelled		6.15
Weighted-Average Exercise Price, Outstanding, Ending balance	$ 4.27	4.27	$ 4.33
Weighted-Average Exercise Price, Exercisable	$ 3.85	$ 3.85
Weighted-Average Remaining Contractual Life (in years), Outstanding		7 years 6 months	8 years 1 month 6 days
Weighted-Average Remaining Contractual Life (in years), Exercisable		6 years 7 months 6 days
Aggregate Intrinsic Value, Outstanding	$ 299	$ 299	$ 1,921
Aggregate Intrinsic Value, Exercisable	$ 299	$ 299

Stock Incentive Plan - Summar_3

Stock Incentive Plan - Summary of Nonvested RSUs (Details) - Restricted Stock Units (RSUs)	6 Months Ended
	Jun. 30, 2020$ / sharesshares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares, Outstanding, Beginning balance | shares	517,750,000
Shares, Granted | shares	206,377,000
Shares, Vested | shares	(140,720,000)
Shares, Forfeited | shares	(29,939,000)
Shares, Outstanding, Ending balance | shares	553,468,000
Weighted-Average Grant Date Fair Value, Outstanding, Beginning balance | $ / shares	$ 2.42
Weighted-Average Grant Date Fair Value, Granted | $ / shares	1.71
Weighted-Average Grant Date Fair Value, Vested | $ / shares	2.42
Weighted-Average Grant Date Fair Value, Forfeited | $ / shares	2.42
Weighted-Average Grant Date Fair Value, Outstanding, Ending balance | $ / shares	$ 2.16