Astria Therapeutics (ATXS) 10-Q 13 May 21 2021 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2021	Apr. 30, 2021
Document and Entity Information
Entity Registrant Name	CATABASIS PHARMACEUTICALS INC
Document Type	10-Q
Document Period End Date	Mar. 31, 2021
Title of 12(b) Security	Common Stock, $0.001 par value per share
Trading Symbol	CATB
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		23,417,006
Entity Central Index Key	0001454789
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q1
Amendment Flag	false

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 146,920	$ 24,930
Short-term investments		20,000
Prepaid expenses and other current assets	764	1,395
Total current assets	147,684	46,325
Right-of-use asset	874	966
Other assets	182	165
Total assets	148,740	47,456
Current liabilities:
Accounts payable	1,809	1,544
Accrued expenses	1,945	4,197
Current portion of operating lease liabilities	652	649
Total current liabilities	4,406	6,390
Warrant liability	4,369
Long-term portion of operating lease liabilities	229	397
Total liabilities	9,004	6,787
Commitments
Series X redeemable convertible preferred stock, $0.001 par value per share, 91,380 shares authorized; 86,077 shares issued and outstanding as of March 31, 2021 and no shares issued and outstanding as of December 31, 2020	240,881
Stockholders' equity (deficit):
Common stock, $0.001 par value per share, 150,000,000 shares authorized; 23,417,006 and 20,084,337 shares issued and outstanding at March 31, 2021 and December 31, 2020, respectively	23	20
Additional paid-in capital	329,813	301,546
Accumulated deficit	(430,981)	(260,897)
Total stockholders' equity (deficit)	(101,145)	40,669
Total liabilities, redeemable convertible preferred stock and stockholders' equity (deficit)	$ 148,740	$ 47,456

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Mar. 31, 2021	Dec. 31, 2020
Condensed Consolidated Balance Sheets
Series X redeemable convertible preferred stock, par value	$ 0.001	$ 0.001
Series X redeemable convertible preferred stock, shares authorized	91,380	91,380
Series X redeemable convertible preferred stock, shares issued	86,077	0
Series X redeemable convertible preferred stock, shares outstanding	86,077	0
Preferred stock, par value (in dollars per share)	$ 0.001
Preferred stock, authorized (in shares)	5,000,000
Preferred stock, outstanding (in shares)	86,077
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, authorized (in shares)	150,000,000	150,000,000
Common stock, issued (in shares)	23,417,006	20,084,337
Common stock, outstanding (in shares)	23,417,006	20,084,337

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Operating expenses:
Research and development	$ 2,593	$ 5,289
General and administrative	2,880	2,753
Acquired in-process research and development	164,612
Total operating expenses	170,085	8,042
Loss from operations	(170,085)	(8,042)
Other income (expense):
Total other income, net	1	90
Net loss	$ (170,084)	$ (7,952)
Net loss per share - basic and diluted (in dollars per share)	$ (7.60)	$ (0.50)
Weighted-average common shares outstanding used in net loss per share - basic and diluted (in shares)	22,380,176	15,898,664

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Condensed Consolidated Statements of Comprehensive Loss
Net loss	$ (170,084)	$ (7,952)
Other comprehensive loss:
Loss on short-term investments		(15)
Total other comprehensive loss:		(15)
Comprehensive loss	$ (170,084)	$ (7,967)

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Redeemable Convertible Preferred Stock	3 Months Ended
	Mar. 31, 2021USD ($)shares
Increase (decrease) in Redeemable Convertible Preferred Stock
Balance, beginning of period (in shares)	0
Balance, end of period (in shares)	86,077
Series X Preferred Stock
Increase (decrease) in Redeemable Convertible Preferred Stock
Balance, beginning of period | $	$ 0
Balance, beginning of period (in shares)	0
Issuance of preferred stock in a private offering of public equity, net of issuance | $	$ 84,696,000
Issuance of preferred stock in a private offering of public equity, net of issuance (in shares)	35,573
Issuance of preferred stock upon acquisition of Quellis | $	$ 156,185,000
Issuance of preferred stock upon acquisition of Quellis (in shares)	50,504
Balance, end of period | $	$ 240,881,000
Balance, end of period (in shares)	86,077

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Stockholders' Equity (Deficit) - USD ($)	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Accumulated other comprehensive loss	Total
Balance, beginning of period at Dec. 31, 2019	$ 12,000	$ 259,305,000	$ (223,597,000)	$ 0
Balance, beginning of period (in shares) at Dec. 31, 2019	12,433,600
Increase (Decrease) in Shareholders' Equity
Issuance of common stock in a public offering, net of issuance costs		24,554,000
Issuance of common stock for at-the-market offerings	$ 1,000	1,059,000
Issuance of common stock for at-the-market offerings (in shares)	173,572
Issuance of common stock and warrants in public offerings	$ 5,000
Issuance of common stock and warrants in public offerings (in shares)	5,290,000
Stock-based compensation expense		339,000
Net loss			(7,952,000)		$ (7,952,000)
Realized loss on short-term investments				(15,000)	(15,000)
Balance, end of period at Mar. 31, 2020	$ 18,000	285,257,000	(231,549,000)	$ (15,000)	53,711,000
Balance, end of period (in shares) at Mar. 31, 2020	17,897,172
Balance, beginning of period at Dec. 31, 2020	$ 20,000	301,546,000	(260,897,000)		$ 40,669,000
Balance, beginning of period (in shares) at Dec. 31, 2020	20,084,337				20,084,337
Increase (Decrease) in Shareholders' Equity
Issuance of preferred stock in a private offering of public equity, net of issuance		19,565,000
Issuance of common stock upon acquisition of Quellis	$ 3,000	8,095,000
Issuance of common stock upon acquisition of Quellis (in shares)	3,332,669
Expense related to warrants inherited in acquisition of Quellis		241,000
Stock-based compensation expense		366,000
Net loss			(170,084,000)		$ (170,084,000)
Balance, end of period at Mar. 31, 2021	$ 23,000	$ 329,813,000	$ (430,981,000)		$ (101,145,000)
Balance, end of period (in shares) at Mar. 31, 2021	23,417,006				23,417,006

Condensed Consolidated Statem_5

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Operating activities
Net loss	$ (170,084)	$ (7,952)
Reconciliation of net loss to net cash used in operating activities:
Non-cash portion of acquired in-process research and development	164,612
Other non-cash items	425	351
Changes in assets and liabilities:
Prepaid expenses and other current assets	767	669
Right-of-use asset-operating	(73)	51
Accounts payable	(1,712)	(501)
Accrued expenses	(2,651)	393
Net cash used in operating activities	(8,716)	(6,989)
Investing activities
Purchases of short-term investments		(42,777)
Sales and maturities of short-term investments	20,000	27,345
Cash acquired in acquisition of Quellis	6,466
Purchases of property and equipment	(21)
Net cash provided by (used in) investing activities	26,445	(15,432)
Financing activities
Proceeds from public offerings, net of issuance costs		24,564
Proceeds from private offering of public equity, net of issuance costs	104,261
Proceeds from at-the-market offering, net of issuance costs		1,060
Net cash provided by financing activities	104,261	25,624
Net increase in cash, cash equivalents and restricted cash	121,990	3,203
Cash, cash equivalents and restricted cash, beginning of period	25,051	10,376
Cash, cash equivalents and restricted cash, end of period	$ 147,041	13,579
Non-cash investing activities:
Fixed asset purchases included in accounts payable		9
Non-cash financing activities:
Public offering issuance costs included in current liabilities		$ 5

Organization and Operations

Organization and Operations	3 Months Ended
	Mar. 31, 2021
Organization and Operations
Organization and Operations	1. Organization and Operations The Company Catabasis Pharmaceuticals, Inc. (the “Company”) is a biopharmaceutical company focused on the discovery, development and commercialization of novel therapeutics. Its mission is to bring hope with life-changing therapies to patients and families. On October 26, 2020, the Company announced that the Phase 3 PolarisDMD trial of the Company’s previous lead product candidate, edasalonexent, for the treatment of Duchenne muscular dystrophy (DMD) did not meet its primary and secondary endpoints. Based on these results, the Company announced that it was stopping activities related to the development of edasalonexent, including the Company’s ongoing open-label extension trial. On January 28, 2021, the Company acquired Quellis Biosciences, Inc ("Quellis"). The Company's lead product candidate, which was acquired in the Quellis acquisition, is QLS-215, a monoclonal antibody inhibitor of plasma kallikrein in preclinical development for the treatment of hereditary angioedema, or HAE, a rare, debilitating and potentially life-threatening disease. The Company was incorporated in the State of Delaware on June 26, 2008. Agreement and Plan of Merger On January 28, 2021, the Company acquired Quellis (the "Quellis Acquisition"). Under the terms of the Merger Agreement, the Company issued to the stockholders of Quellis 3,332,669 shares of the Company's common stock, par value $0.001 per share, and 50,504 shares of newly designated Series X redeemable convertible preferred stock (“Series X Preferred Stock”) (as described below). The Series X Preferred Stock had a conversion value on the closing date of $122.7 million. In addition, the Company assumed options granted under the Quellis stock option plan, which became options to purchase 332,494 shares of the Company’s common stock, a warrant to purchase 2,805 shares of Series X Preferred Stock at an exercise price of $341.70 per share, and a warrant to purchase 185,136 shares of the Company's common stock at an exercise price of $0.35 per share, which warrants are exercisable until December 14, 2030. Stock Purchase Agreement and Series X Preferred Stock Concurrent with the Quellis Acquisition, the Company entered into a Stock Purchase Agreement (the "Purchase Agreement") with certain institutional and accredited investors. Pursuant to the Purchase Agreement, the Company sold an aggregate of 35,573 shares of Series X Preferred Stock for gross proceeds of approximately $110.0 million, and net proceeds of $104.3 million (the "February 2021 Financing"). In accounting for the Purchase Agreement, the Company recorded a beneficial conversion feature of $19.6 million, which is included in Additional Paid in Capital in the accompanying Condensed Consolidated Balance Sheet as of March 31, 2021. As a result of the Quellis Acquisition and the February 2021 Financing, in 2021 the Company issued the following Series X Preferred Stock or warrants to purchase Series X Preferred Stock: Series X Common Stock Preferred Issuable Upon Stock Conversion (1) Outstanding shares issued in merger 50,504 50,504,000 Outstanding shares issued in February 2021 Financing 35,573 35,573,000 Warrants assumed in merger 2,805 2,805,000 Total 88,882 88,882,000 (1) Subject to stockholder approval, each share of Series X Preferred Stock is convertible into 1,000 shares of common stock. The Company is required to hold a stockholders’ meeting to request the approval of the conversion of the Series X Preferred Stock into shares of the Company’s common stock in accordance with Nasdaq Listing Rule 5635(a) (the “Conversion Proposal”). The Company has scheduled its 2021 Annual Meeting of Stockholders for June 2, 2021 and has included the Conversion Proposal as one of the proposals to be voted on at the meeting. If the Company's stockholders do not approve the conversion of the Series X Preferred Stock by July 28, 2021, then the holders of the Series X Preferred Stock are entitled to require the Company to make redemption payments at a price per share equal to the fair value of undelivered shares of common stock, defined as the last reported closing price of the Company's common stock on the trading day on which notice of conversion is delivered to the Company. Using the closing price on May 10, 2021 of $1.86, if all currently outstanding Series X Preferred Stock was redeemed for cash, the Company would be required to make a payment of $160.1 million. The Company has insufficient liquidity to make such a payment, if required. Holders of Series X Preferred Stock are entitled to receive dividends on shares of Series X Preferred Stock equal, on an as-if-converted-to-common-stock basis, and in the same form as dividends actually paid on shares of the Company's common stock. Except as otherwise required by law, the Series X Preferred Stock does not have voting rights. However, as long as any shares of Series X Preferred Stock are outstanding, the Company may not, without the affirmative vote of the holders of a majority of the then outstanding shares of the Series X Preferred Stock, (i) alter or change adversely the powers, preferences or rights given to the Series X Preferred Stock or alter or amend the Certificate of Designation that authorized the Series X Preferred Stock, amend or repeal any provision of, or add any provision to, the Company's Certificate of Incorporation or bylaws, or file any articles of amendment, certificate of designations, preferences, limitations and relative rights of any series of preferred stock, if such action would adversely alter or change the preferences, rights, privileges or powers of, or restrictions provided for the benefit of the Series X Preferred Stock, (ii) issue further shares of Series X Preferred Stock or increase or decrease (other than by conversion) the number of authorized shares of Series X Preferred Stock, or (iii) enter into any agreement with respect to any of the foregoing. Additionally, the approval of the holders of a majority of the Series X Preferred Stock is required for certain change of control transactions, provided that this approval right will terminate upon stockholder approval of the Conversion Proposal. Following stockholder approval of the Conversion Proposal, on the fourth business day after the date on which such stockholder approval is received, each share of Series X Preferred Stock then outstanding automatically converts into 1,000 shares of the Company's common stock, subject to certain beneficial ownership limitations, including that a holder of Series X Preferred Stock is prohibited from converting shares of Series X Preferred Stock into shares of the Company's common stock if, as a result of such conversion, such holder, together with its affiliates, would beneficially own more than a specified percentage (to be initially set at 9.99% and thereafter adjustable by the holder to a number between 4.99% and 19.99)% of the total number of shares of the Company's common stock issued and outstanding immediately after giving effect to such conversion. Shares of Series X Preferred Stock not converted automatically are thereafter subject to conversion at the option of the holder. January 2020 Financing On January 30, 2020, the Company entered into an underwriting agreement with Oppenheimer & Co. Inc. relating to an underwritten public offering (the “January 2020 Financing”) of 5,290,000 shares of common stock at a price to the public of $5.00 per share, including 690,000 shares issued upon the exercise in full by Oppenheimer & Co. Inc. of its overallotment option. This resulted in gross proceeds of $26.5 million, and net proceeds of $24.6 million. Liquidity The Company has entered into various sales agreements with Cowen and Company LLC (“Cowen”), pursuant to which the Company could issue and sell shares of common stock, par value of $0.001 per share, under at-the-market offering programs (the “ATM Programs”). The Company pays Cowen 3% of the gross proceeds from any common stock sold through these sales agreements. On May 10, 2021, the Company notified Cowen that it was terminating its current sales agreement with Cowen, such termination to take effect on May 20, 2021. During the three months ended March 31, 2020, the Company sold an aggregate of 173,572 shares of common stock pursuant to the ATM Programs, at an average price of $6.29 per share, for net proceeds of $1.1 million after deducting sales commissions and offering expenses. There was no activity from the ATM Programs during the three months ended March 31, 2021. As of March 31, 2021, the Company had an accumulated deficit of $431.0 million. The Company has been primarily involved with research and development activities and has incurred operating losses and negative cash flows from operations since its inception. The Company has not generated any product revenues and has financed its operations primarily through public offerings and private placements of its equity securities. There can be no assurance that the Company will be able to obtain additional debt, equity or other financing or generate product revenue or revenues from collaborative partners, on terms acceptable to the Company, on a timely basis or at all. The failure of the Company to obtain sufficient funds on acceptable terms when needed could have a material adverse effect on the Company's business, results of operations, and financial condition. The Company is subject to a number of risks similar to other life science companies, including, but not limited to, successful discovery and development of its drug candidates, raising additional capital, development by its competitors of new technological innovations, protection of proprietary technology and regulatory approval and market acceptance of the Company's products. The Company has been primarily involved with research and development activities and has incurred operating losses and negative cash flows from operations since its inception. The Company anticipates that it will continue to incur significant operating losses for the next several years as it continues to develop its product candidates. As of March 31, 2021, the Company had available cash and cash equivalents of $146.9 million. As part of the Quellis Acquisition and the February 2021 Financing, the Company issued 86,077 shares of Series X Preferred Stock, which upon stockholder approval, will be converted to 86,077,000 shares of common stock, subject to applicable beneficial ownership limitations. The terms of the Series X Preferred Stock include a cash redemption feature which, as described above, provide that, if the Company’s stockholders fail to approve the Conversion Proposal by July 28, 2021, the Company could be required to make redemption payments to the holders of Series X Preferred Stock significantly in excess of its current liquidity. Based on precedent transactions and the terms of the Series X Preferred Stock, the Company believes that stockholders who are entitled to vote on the Conversion Proposal at the Company’s 2021 Annual Meeting of Stockholders, which is scheduled for June 2, 2021, will vote to approve the proposal. However, as the vote of the Company’s common stockholders is outside of the control of the Company, there is substantial doubt about its ability to continue as a going concern for at least 12 months following the issuance of these condensed consolidated financial statements. The accompanying condensed consolidated financial statements have been prepared on a going concern basis, which contemplates the realization of assets and satisfaction of liabilities in the ordinary course of business. The condensed consolidated financial statements do not include any adjustments relating to the recoverability and classification of recorded asset amounts or the amounts and classification of liabilities that might result from the outcome of this uncertainty.

Summary of Significant Accounti

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2021
Summary of Significant Accounting Policies
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Basis of Presentation and Principles of Consolidation The accompanying financial statements and the related disclosures are unaudited and have been prepared in accordance with United States generally accepted accounting principles (“U.S. GAAP”). Additionally, certain information and footnote disclosures normally included in the Company’s annual financial statements have been condensed or omitted from this report. Accordingly, these condensed financial statements should be read in conjunction with the financial statements as of and for the year ended December 31, 2020 and notes thereto included in the Company's 2020 Annual Report on Form 10-K. The unaudited interim condensed 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, including those adjustments that are of a normal and recurring nature, which are necessary to fairly present the Company’s results for the interim periods presented. The results for the three months ended March 31, 2021 are not necessarily indicative of the results for the year ending December 31, 2021, or for any future period. The accompanying condensed consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries, Catabasis Securities Corporation and Quellis Biosciences, LLC, successor in interest to Quellis. All intercompany balances and transactions have been eliminated in consolidation. Use of Estimates The preparation of the Company’s condensed consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the amounts reported in the condensed consolidated financial statements and accompanying notes. Actual results could differ from such estimates. The Company utilizes certain estimates to record expenses relating to research and development contracts. These contract estimates, which are primarily related to the length of service of each contract and the amount of service provided as of each measurement date, are determined by the Company based on input from internal project management, as well as from the Company's service providers. Derivative Instruments The Company generally does not use derivative instruments to hedge exposures to cash-flow or market risks; however, certain warrants to purchase preferred stock that do not meet the requirements for classification as equity are classified as liabilities. Such financial instruments are initially recorded at fair value, with subsequent changes in fair value charged to operations in each reporting period. If these instruments subsequently meet the requirements for classification as equity, the Company reclassifies the fair value to equity. Net Loss Per Share Basic net loss per share is calculated by dividing net loss by the weighted average shares outstanding during the period, without consideration for common stock equivalents. Diluted net loss per share is calculated by adjusting weighted average shares outstanding for the dilutive effect of common stock equivalents outstanding for the period, determined using the treasury-stock method. For purposes of the Company’s dilutive net loss per share calculation, preferred stock, stock options and warrants to purchase common stock and preferred stock were considered to be common stock equivalents but were excluded from the calculation of diluted net loss per share, as their effect would be anti-dilutive; therefore, basic and diluted net loss per share were the same for all periods presented. The following common stock equivalents were excluded from the calculation of diluted net loss per share for the periods indicated because including them would have had an anti-dilutive effect: Three Months Ended March 31, 2021 2020 Series X Preferred Stock (1) — Stock options 1,631,322 1,206,644 Common stock warrants 6,378,885 6,193,749 Preferred stock warrants (1) 2,805,000 — 96,892,207 7,400,393 (1) Shown as common stock equivalents Cash, Cash Equivalents and Restricted Cash The reconciliation of cash, cash equivalents and restricted cash reported within the applicable balance sheet that sum to the total of the same such amount shown in the statement of cash flows is as follows (in thousands): March 31, 2021 2020 Cash and cash equivalents $ 146,920 $ 13,344 Restricted cash (1) 121 235 Total $ 147,041 $ 13,579 (1) Acquired In-Process Research and Development The Company measures and recognizes asset acquisitions that are not deemed to be business combinations based on the cost to acquire the assets, which includes transaction costs. Goodwill is not recognized in asset acquisitions. In an asset acquisition, the cost allocated to acquire in-process research and development (“IPR&D”) with no alternative future use is charged to expense at the acquisition date. Refer to Note 3, “Acquisition of Quellis” for a more detailed description of the accounting policy utilized for the recent asset acquisition. Recent Accounting Pronouncements - Not Yet Adopted From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board (“FASB”) or other standard setting bodies and adopted by the Company as of the specified effective date. In June 2016, the FASB issued Accounting Standards Update (“ASU”) 2016-13, Financial Instruments-Credit Losses (Topic 326). This standard requires a financial asset to be presented at amortized cost basis at the net amount expected to be collected. It also requires that credit losses relating to available-for-sale debt securities should be recorded through an allowance for credit losses. In November 2019, the FASB issued an amendment making this ASU effective for annual reporting periods beginning after December 15, 2022 for smaller reporting companies, early adoption is permitted. The Company is currently evaluating the impact that this standard will have on its consolidated financial statements. Summary of Significant Accounting Policies The Company’s significant accounting policies are described in Note 2, “Summary of Significant Accounting Policies,” in the Company's 2020 Annual Report on Form 10-K, and there were no significant changes to such policies in the three months ended March 31, 2021 that had a material impact on the Company’s results of operations or financial position.

Acquisition of Quellis

Acquisition of Quellis	3 Months Ended
	Mar. 31, 2021
Acquisition of Quellis
Acquisition of Quellis	3. Acquisition of Quellis On January 28, 2021, the Company completed its acquisition of Quellis in accordance with the terms of the Merger Agreement as discussed in Note 1, “Organization and Operations” . Under the terms of the Merger Agreement, the Company issued 3,332,669 shares of Common Stock and 50,504 shares of Series X Preferred Stock. Each share of Series X Preferred Stock is convertible into 1,000 shares of Common Stock, subject to certain conditions. The Company concluded that the Quellis Acquisition was not the acquisition of a business, as substantially all of the fair value of the non-monetary assets acquired was concentrated in a single identifiable asset, QLS-215. The Company determined that the cost to acquire the Quellis assets was $170.7 million, based on the fair value of the equity consideration issued and including direct costs of the acquisition of $1.8 million. The net assets acquired in connection with the Quellis Acquisition were recorded at their estimated fair values as of January 28, 2021, which is the date the Quellis Acquisition was completed. The following table summarizes the net assets acquired based on their estimated fair values as of January 28, 2021 (in thousands): Acquired IPR&D $ 164,612 Cash and cash equivalents 8,307 Prepaid expenses and other assets 136 Accounts payable (1,974) Accrued liabilities (400) Net acquired tangible assets $ 170,681 In the estimation of fair value of the asset purchase consideration, the Company used the carrying value of the cash and cash equivalents, prepaid expenses, accounts payable, and accrued liabilities as the most reliable indicator of fair value based on the associated short-term nature of the balances. The remaining fair value was attributable to the acquired IPR&D. As QLS-215 had not, at the time of the Quellis Acquisition, received regulatory approval in any territory, the cost attributable to the IPR&D was expensed in the Company's consolidated statements of operations and comprehensive loss for the three months ended March 31, 2021 as the acquired IPR&D had no alternative future use, as determined by the Company in accordance with U.S. GAAP.

Financial Instruments

Financial Instruments	3 Months Ended
	Mar. 31, 2021
Financial Instruments
Financial Instruments	4. Financial Instruments The tables below present information about the Company’s assets and liabilities that are measured at fair value on a recurring basis as of March 31, 2021 and December 31, 2020 and indicate the fair value hierarchy of the valuation techniques the Company utilized to determine such fair value. In general, fair values determined by Level 1 inputs utilize observable inputs such as quoted prices in active markets for identical assets or liabilities. Fair values determined by Level 2 inputs utilize data points that are either directly or indirectly observable, such as quoted prices, interest rates and yield curves. Fair values determined by Level 3 inputs utilize unobservable data points for which there is little or no market data, which require the Company to develop its own assumptions for the asset or liability. There were no transfers between fair value measurement levels during the three months ended March 31, 2021 or 2020. The Company’s investment portfolio may include fixed income securities that do not always trade on a daily basis. As a result, the pricing services used by the Company apply other available information as applicable through processes such as benchmark yields, benchmarking of like securities, sector groupings and matrix pricing to prepare valuations. The Company validates the prices provided by its third party pricing services by obtaining market values from other pricing sources and analyzing pricing data in certain instances. The Company has from time to time invested in certain reverse repurchase agreements which are collateralized by deposits in the form of U.S. Government Securities and Obligations for an amount no less than 102% of their value. The Company has not recorded an asset or liability for the collateral as the Company was not permitted to sell or re-pledge the collateral. The collateral had at least the prevailing credit rating of U.S. Government Treasuries and Agencies. The Company utilized a third party custodian to manage the exchange of funds and ensure that collateral received is maintained at 102% of the value of the reverse repurchase agreements on a daily basis. The Company accounts for warrants to purchase its stock pursuant to Accounting Standards Codification (“ASC”) Topic 470, Debt , and ASC Topic 480, Distinguishing Liabilities from Equity , and classifies warrants for common stock and preferred stock as liabilities or equity. The warrants classified as liabilities are reported at their estimated fair value and any changes in fair value are reflected in other income, expense. The warrants classified as equity are reported at their estimated fair value with no subsequent remeasurement. Below is a summary of assets and liabilities measured at fair value on a recurring basis (in thousands): As of March 31, 2021 Quoted Prices Significant Significant in Active Observable Unobservable Markets Inputs Inputs (Level 1) (Level 2) (Level 3) Total Assets: Cash and cash equivalents: Money market funds $ 1,833 $ — $ — $ 1,833 Reverse repurchase agreements — 39,000 — 39,000 Total assets $ 1,833 $ 39,000 $ — $ 40,833 Liabilities: Warrant liability $ — $ — $ 4,369 $ 4,369 Total liabilities $ — $ — $ 4,369 $ 4,369 As of December 31, 2020 Quoted Prices Significant Significant in Active Observable Unobservable Markets Inputs Inputs (Level 1) (Level 2) (Level 3) Total Assets: Cash and cash equivalents: Money market funds $ 22,999 $ — $ — $ 22,999 Short-term investments: Reverse repurchase agreements — 20,000 — 20,000 Total assets $ 22,999 $ 20,000 $ — $ 42,999 At March 31, 2021, and December 31, 2020, cash equivalents approximated their fair value due to their short-term nature. The warrant liability was valued based on significant inputs not observable in the market, which represents a Level 3 measurement within the fair value hierarchy. The Company estimates the fair value of the warrant liability using Black-Scholes option-pricing models and assumptions that are based on the individual characteristics of the warrants on the valuation date, as well as assumptions including the fair value per share of the underlying security, the remaining contractual term of the warrant, risk-free interest rate, expected dividend yield and expected volatility of the price of the underlying security. March 31, 2021 Beginning balance $ — Issuance of liability classified warrants 4,332 Change in fair value and current period expense 37 Ending balance $ 4,369

Short-Term Investments

Short-Term Investments	3 Months Ended
	Mar. 31, 2021
Short-Term Investments
Short-Term Investments	5. Short-Term Investments The Company did not hold any short-term investments at March 31, 2021. The following table summarizes the short-term investments held at December 31, 2020 (in thousands): Gross Unrealized Gross Unrealized Amortized Cost Gains Losses Fair Value December 31, 2020 Reverse repurchase agreements $ 20,000 $ — $ — $ 20,000 Total $ 20,000 $ — $ — $ 20,000 The contractual maturities of all short-term investments held at December 31, 2020 were one year or less. There were no short-term investments in an unrealized loss position at December 31, 2020. Gross realized gains and losses on the sales of short-term investments are included in other income, net. Unrealized holding gains or losses for the period that have been included in accumulated other comprehensive income, as well as gains and losses reclassified out of accumulated other comprehensive income into other income, net were not material to the Company’s condensed consolidated results of operations. The cost of investments sold or the amount reclassified out of the accumulated other comprehensive income into other income, net is based on the specific identification method for purposes of recording realized gains and losses. All proceeds in the three-month periods ended March 31, 2021 and 2020 related to maturities of underlying investments. T

Accrued Expenses

Accrued Expenses	3 Months Ended
	Mar. 31, 2021
Accrued Expenses
Accrued Expenses	6. Accrued Expenses Accrued expenses consisted of the following (in thousands): March 31, December 31, 2021 2020 Accrued compensation $ 704 $ 1,719 Accrued other 384 — Accrued professional fees 371 356 Accrued severance 205 396 Accrued contracted research costs 281 1,726 Total $ 1,945 $ 4,197

Stockholders' Equity

Stockholders' Equity	3 Months Ended
	Mar. 31, 2021
Stockholders' Equity
Stockholders' Equity	7. Stockholders’ Equity Preferred Stock Under the Company's amended and restated certificate of incorporation, the Company has 5,000,000 shares of preferred stock authorized for issuance, with a $0.001 par value per share. Preferred stock may be issued from time to time in one or more series, each series to have such terms as stated or expressed in the resolutions providing for the issue of such series adopted by the board of directors of the Company. Preferred stock which may be redeemed, purchased or acquired by the Company may be reissued except as otherwise provided by law. As of March 31, 2021, the Company had 86,077 shares of Series X preferred stock outstanding. Refer to Note 1 “Organization and Operations ” regarding the Company's issuance of Series X Preferred Stock in January 2021 and February 2021. Outstanding Warrants The following table presents information about warrants that are issued and outstanding at March 31, 2021: Year Issued Equity Instrument Warrants Outstanding Exercise Price Date of Expiration 2014 Common Stock 1,227 $ 122.12 8/26/2021 2015 Common Stock 1,227 $ 122.12 3/30/2022 2018 Common Stock 4,199,995 $ 12.00 6/21/2023 2019 Common Stock 1,991,300 $ 6.25 2/7/2024 2021 Common Stock 185,136 $ 0.35 12/14/2030 2021 (1) Series X Preferred Stock 2,805,000 $ 0.34 12/14/2030 Total 9,183,885 Weighted average exercise price $ 6.99 Weighted average life in years 4.80 (1) Includes 2,805 warrants exercisable for Series X Preferred Stock at an exercise price of $341.17 shown as common stock equivalents

Reserved for Future Issuance

Reserved for Future Issuance	3 Months Ended
	Mar. 31, 2021
Reserved for Future Issuance
Reserved for Future Issuance	8. Reserved for Future Issuance The Company has reserved for future issuance the following shares of common stock: March 31, December 31, 2021 2020 Warrants for the purchase of common stock 6,378,885 6,193,749 Options outstanding to purchase common stock 1,631,322 1,367,667 Options available for future issuance to purchase common stock 1,996,322 1,936,173 Shares reserved for the employee stock purchase plan 185,421 148,951 Total 10,191,950 9,646,540 As of March 31, 2021, the Company also had 86,077 shares of Series X Preferred Stock and 2,805 Series X Preferred Stock warrants outstanding. Following stockholder approval of the Conversion Proposal, on the fourth business day after the date on which such stockholder approval is received, each share of Series X Preferred Stock then outstanding automatically converts into 1,000 shares of the Company's common stock, subject to certain beneficial ownership limitations. See Note 1 “Organization and Operations ” for additional detail.

Stock Incentive Plans

Stock Incentive Plans	3 Months Ended
	Mar. 31, 2021
Stock Incentive Plans
Stock Incentive Plans	9. Stock Incentive Plans A summary of the Company’s stock option activity and related information follows: Weighted Average Weighted- Remaining Aggregate Average Exercise Contractual Intrinsic Value Shares Price Term (years) (in thousands) Outstanding at December 31, 2020 1,367,667 $ $ — Granted 30,000 $ Assumed in Quellis Acquisition 332,494 $ Cancelled or forfeited $ Expired $ Outstanding at March 31, 2021 1,631,322 $ $ 879 Vested and exercisable at March 31, 2021 622,533 $ $ — There were no options exercised in the three months ended March 31, 2021 and 2020. The total grant date fair value of options vested for the three months ended March 31, 2021 and 2020 was $0.5 million and $0.4 million, respectively. The weighted-average grant date fair value of options granted to employees and non-employees for the three months ended March 31, 2021 and 2020 was $1.50 and $3.57, respectively. At March 31, 2021, the total unrecognized compensation expense related to unvested stock option awards was $2.8 million. The Company expects to recognize that cost over a weighted-average period of approximately 2.2 years.

Subsequent Events

Subsequent Events	3 Months Ended
	Mar. 31, 2021
Subsequent Events
Subsequent Events	10. Subsequent Events The Company considers events or transactions that occur after the balance sheet date but prior to the issuance of the financial statements to provide additional evidence for certain estimates and to identify matters that require additional disclosure. Subsequent events have been evaluated as required.

Summary of Significant Accoun_2

Summary of Significant Accounting Polices (Polices)	3 Months Ended
	Mar. 31, 2021
Summary of Significant Accounting Policies
Basis of Presentation and Principles of Consolidation	Basis of Presentation and Principles of Consolidation The accompanying financial statements and the related disclosures are unaudited and have been prepared in accordance with United States generally accepted accounting principles (“U.S. GAAP”). Additionally, certain information and footnote disclosures normally included in the Company’s annual financial statements have been condensed or omitted from this report. Accordingly, these condensed financial statements should be read in conjunction with the financial statements as of and for the year ended December 31, 2020 and notes thereto included in the Company's 2020 Annual Report on Form 10-K. The unaudited interim condensed 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, including those adjustments that are of a normal and recurring nature, which are necessary to fairly present the Company’s results for the interim periods presented. The results for the three months ended March 31, 2021 are not necessarily indicative of the results for the year ending December 31, 2021, or for any future period. The accompanying condensed consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries, Catabasis Securities Corporation and Quellis Biosciences, LLC, successor in interest to Quellis. All intercompany balances and transactions have been eliminated in consolidation.
Use of Estimates	Use of Estimates The preparation of the Company’s condensed consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the amounts reported in the condensed consolidated financial statements and accompanying notes. Actual results could differ from such estimates. The Company utilizes certain estimates to record expenses relating to research and development contracts. These contract estimates, which are primarily related to the length of service of each contract and the amount of service provided as of each measurement date, are determined by the Company based on input from internal project management, as well as from the Company's service providers.
Derivative Instruments	Derivative Instruments The Company generally does not use derivative instruments to hedge exposures to cash-flow or market risks; however, certain warrants to purchase preferred stock that do not meet the requirements for classification as equity are classified as liabilities. Such financial instruments are initially recorded at fair value, with subsequent changes in fair value charged to operations in each reporting period. If these instruments subsequently meet the requirements for classification as equity, the Company reclassifies the fair value to equity.
Net Loss Per Share	Net Loss Per Share Basic net loss per share is calculated by dividing net loss by the weighted average shares outstanding during the period, without consideration for common stock equivalents. Diluted net loss per share is calculated by adjusting weighted average shares outstanding for the dilutive effect of common stock equivalents outstanding for the period, determined using the treasury-stock method. For purposes of the Company’s dilutive net loss per share calculation, preferred stock, stock options and warrants to purchase common stock and preferred stock were considered to be common stock equivalents but were excluded from the calculation of diluted net loss per share, as their effect would be anti-dilutive; therefore, basic and diluted net loss per share were the same for all periods presented. The following common stock equivalents were excluded from the calculation of diluted net loss per share for the periods indicated because including them would have had an anti-dilutive effect: Three Months Ended March 31, 2021 2020 Series X Preferred Stock (1) — Stock options 1,631,322 1,206,644 Common stock warrants 6,378,885 6,193,749 Preferred stock warrants (1) 2,805,000 — 96,892,207 7,400,393 (1) Shown as common stock equivalents
Cash, Cash Equivalents and Restricted Cash	Cash, Cash Equivalents and Restricted Cash The reconciliation of cash, cash equivalents and restricted cash reported within the applicable balance sheet that sum to the total of the same such amount shown in the statement of cash flows is as follows (in thousands): March 31, 2021 2020 Cash and cash equivalents $ 146,920 $ 13,344 Restricted cash (1) 121 235 Total $ 147,041 $ 13,579 (1)
Acquired In-Process Research and Development	Acquired In-Process Research and Development The Company measures and recognizes asset acquisitions that are not deemed to be business combinations based on the cost to acquire the assets, which includes transaction costs. Goodwill is not recognized in asset acquisitions. In an asset acquisition, the cost allocated to acquire in-process research and development (“IPR&D”) with no alternative future use is charged to expense at the acquisition date. Refer to Note 3, “Acquisition of Quellis” for a more detailed description of the accounting policy utilized for the recent asset acquisition.
Recent Accounting Pronouncements - Not Yet Adopted	Recent Accounting Pronouncements - Not Yet Adopted From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board (“FASB”) or other standard setting bodies and adopted by the Company as of the specified effective date. In June 2016, the FASB issued Accounting Standards Update (“ASU”) 2016-13, Financial Instruments-Credit Losses (Topic 326). This standard requires a financial asset to be presented at amortized cost basis at the net amount expected to be collected. It also requires that credit losses relating to available-for-sale debt securities should be recorded through an allowance for credit losses. In November 2019, the FASB issued an amendment making this ASU effective for annual reporting periods beginning after December 15, 2022 for smaller reporting companies, early adoption is permitted. The Company is currently evaluating the impact that this standard will have on its consolidated financial statements.
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies The Company’s significant accounting policies are described in Note 2, “Summary of Significant Accounting Policies,” in the Company's 2020 Annual Report on Form 10-K, and there were no significant changes to such policies in the three months ended March 31, 2021 that had a material impact on the Company’s results of operations or financial position

Organization and Operations (Ta

Organization and Operations (Tables)	3 Months Ended
	Mar. 31, 2021
Organization and Operations
Schedule of common stock warrants outstanding	Series X Common Stock Preferred Issuable Upon Stock Conversion (1) Outstanding shares issued in merger 50,504 50,504,000 Outstanding shares issued in February 2021 Financing 35,573 35,573,000 Warrants assumed in merger 2,805 2,805,000 Total 88,882 88,882,000 (1)

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	3 Months Ended
	Mar. 31, 2021
Summary of Significant Accounting Policies
Schedule of anti-dilutive common stock equivalents excluded from calculation of diluted net loss per share	Three Months Ended March 31, 2021 2020 Series X Preferred Stock (1) — Stock options 1,631,322 1,206,644 Common stock warrants 6,378,885 6,193,749 Preferred stock warrants (1) 2,805,000 — 96,892,207 7,400,393 (1) Shown as common stock equivalents
Schedule of reconciliation of cash, cash equivalents and restricted cash	March 31, 2021 2020 Cash and cash equivalents $ 146,920 $ 13,344 Restricted cash (1) 121 235 Total $ 147,041 $ 13,579 (1)

Acquisition of Quellis (Tables)

Acquisition of Quellis (Tables)	3 Months Ended
	Mar. 31, 2021
Acquisition of Quellis
Schedule of net assets acquired	The following table summarizes the net assets acquired based on their estimated fair values as of January 28, 2021 (in thousands): Acquired IPR&D $ 164,612 Cash and cash equivalents 8,307 Prepaid expenses and other assets 136 Accounts payable (1,974) Accrued liabilities (400) Net acquired tangible assets $ 170,681

Financial Instruments (Tables)

Financial Instruments (Tables)	3 Months Ended
	Mar. 31, 2021
Financial Instruments
Schedule of assets and liabilities measured fair value on recurring basis	Below is a summary of assets and liabilities measured at fair value on a recurring basis (in thousands): As of March 31, 2021 Quoted Prices Significant Significant in Active Observable Unobservable Markets Inputs Inputs (Level 1) (Level 2) (Level 3) Total Assets: Cash and cash equivalents: Money market funds $ 1,833 $ — $ — $ 1,833 Reverse repurchase agreements — 39,000 — 39,000 Total assets $ 1,833 $ 39,000 $ — $ 40,833 Liabilities: Warrant liability $ — $ — $ 4,369 $ 4,369 Total liabilities $ — $ — $ 4,369 $ 4,369 As of December 31, 2020 Quoted Prices Significant Significant in Active Observable Unobservable Markets Inputs Inputs (Level 1) (Level 2) (Level 3) Total Assets: Cash and cash equivalents: Money market funds $ 22,999 $ — $ — $ 22,999 Short-term investments: Reverse repurchase agreements — 20,000 — 20,000 Total assets $ 22,999 $ 20,000 $ — $ 42,999
Summary of derivative warrant liability was valued based on significant inputs not observable in the market, which represents a Level 3	March 31, 2021 Beginning balance $ — Issuance of liability classified warrants 4,332 Change in fair value and current period expense 37 Ending balance $ 4,369

Short-Term Investments (Tables)

Short-Term Investments (Tables)	3 Months Ended
	Mar. 31, 2021
Short-Term Investments
Schedule of short term investments	The Company did not hold any short-term investments at March 31, 2021. The following table summarizes the short-term investments held at December 31, 2020 (in thousands): Gross Unrealized Gross Unrealized Amortized Cost Gains Losses Fair Value December 31, 2020 Reverse repurchase agreements $ 20,000 $ — $ — $ 20,000 Total $ 20,000 $ — $ — $ 20,000

Accrued Expenses (Tables)

Accrued Expenses (Tables)	3 Months Ended
	Mar. 31, 2021
Accrued Expenses
Schedule of accrued expenses	Accrued expenses consisted of the following (in thousands): March 31, December 31, 2021 2020 Accrued compensation $ 704 $ 1,719 Accrued other 384 — Accrued professional fees 371 356 Accrued severance 205 396 Accrued contracted research costs 281 1,726 Total $ 1,945 $ 4,197

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	3 Months Ended
	Mar. 31, 2021
Stockholders' Equity
Summary of Series X preferred stock or warrants to purchase	The following table presents information about warrants that are issued and outstanding at March 31, 2021: Year Issued Equity Instrument Warrants Outstanding Exercise Price Date of Expiration 2014 Common Stock 1,227 $ 122.12 8/26/2021 2015 Common Stock 1,227 $ 122.12 3/30/2022 2018 Common Stock 4,199,995 $ 12.00 6/21/2023 2019 Common Stock 1,991,300 $ 6.25 2/7/2024 2021 Common Stock 185,136 $ 0.35 12/14/2030 2021 (1) Series X Preferred Stock 2,805,000 $ 0.34 12/14/2030 Total 9,183,885 Weighted average exercise price $ 6.99 Weighted average life in years 4.80 Includes 2,805 warrants exercisable for Series X Preferred Stock at an exercise price of $341.17 shown as common stock equivalents

Reserved For Future Issuance (T

Reserved For Future Issuance (Tables)	3 Months Ended
	Mar. 31, 2021
Reserved for Future Issuance
Schedule of common stock reserved for future issuance	March 31, December 31, 2021 2020 Warrants for the purchase of common stock 6,378,885 6,193,749 Options outstanding to purchase common stock 1,631,322 1,367,667 Options available for future issuance to purchase common stock 1,996,322 1,936,173 Shares reserved for the employee stock purchase plan 185,421 148,951 Total 10,191,950 9,646,540

Stock Incentive Plans (Tables)

Stock Incentive Plans (Tables)	3 Months Ended
	Mar. 31, 2021
Stock Incentive Plans
Summary of stock option activity	Weighted Average Weighted- Remaining Aggregate Average Exercise Contractual Intrinsic Value Shares Price Term (years) (in thousands) Outstanding at December 31, 2020 1,367,667 $ $ — Granted 30,000 $ Assumed in Quellis Acquisition 332,494 $ Cancelled or forfeited $ Expired $ Outstanding at March 31, 2021 1,631,322 $ $ 879 Vested and exercisable at March 31, 2021 622,533 $ $ —

Organization and Operations - A

Organization and Operations - Agreement and Plan of Merger (Details) - USD ($) $ / shares in Units, $ in Millions	Jan. 28, 2021	Mar. 31, 2021	Mar. 31, 2020
Class of Stock [Line Items]
Assumed in Quellis Acquisition		332,494
Quellis Biosciences, Inc | Stock Purchase Agreement
Class of Stock [Line Items]
Adjustments to Additional Paid in Capital, Convertible Debt with Conversion Feature		$ 19.6
Common Stock
Class of Stock [Line Items]
Shares issued on acquisition (in shares)		3,332,669
Aggregate shares sold under purchase agreement			5,290,000
Common Stock | Quellis Biosciences, Inc
Class of Stock [Line Items]
Shares issued on acquisition (in shares)	3,332,669
Share price (in dollars per share)	$ 0.001
Exercise Price (in dollars per share)	$ 0.35
Series X Preferred Stock
Class of Stock [Line Items]
Exercise Price (in dollars per share)		$ 341.17
Series X Preferred Stock | Quellis Biosciences, Inc
Class of Stock [Line Items]
Shares issued on acquisition (in shares)		86,077
Conversion value	$ 122.7
Conversion shares	50,504
Warrants to purchase number of shares	2,805
Exercise Price (in dollars per share)	$ 341.70
Series X Preferred Stock | Quellis Biosciences, Inc | Stock Purchase Agreement
Class of Stock [Line Items]
Aggregate shares sold under purchase agreement		35,573
Gross proceeds from public offering		$ 110
Net proceeds from public offering		$ 104.3
Series X Preferred Stock | Common Stock
Class of Stock [Line Items]
Assumed in Quellis Acquisition	332,494
Series X Preferred Stock | Common Stock | Quellis Biosciences, Inc
Class of Stock [Line Items]
Warrants to purchase number of shares	185,136

Organization and Operations - S

Organization and Operations - Stock Purchase Agreement and Series X Preferred Stock (Details) - USD ($) $ / shares in Units, $ in Millions	May 10, 2021	Mar. 31, 2021	Feb. 28, 2021	Dec. 31, 2020
Class of Stock [Line Items]
Preferred stock, outstanding		86,077
Common stock, outstanding (in shares)		23,417,006		20,084,337
Convertible preferred stock shares issued upon conversion		1,000
Percentage of beneficial ownership initially, after conversion		9.99%
Series X Preferred Stock
Class of Stock [Line Items]
Preferred stock, outstanding		86,077	88,882
Common stock, outstanding (in shares)			88,882,000
Convertible preferred stock shares issued upon conversion		1,000
Outstanding shares issued in merger
Class of Stock [Line Items]
Preferred stock, outstanding			50,504
Common stock, outstanding (in shares)			50,504,000
Outstanding shares issued in February 2021 Financing
Class of Stock [Line Items]
Preferred stock, outstanding			35,573
Common stock, outstanding (in shares)			35,573,000
Warrants assumed in merger
Class of Stock [Line Items]
Preferred stock, outstanding			2,805
Common stock, outstanding (in shares)			2,805,000
Subsequent Events | Series X Preferred Stock
Class of Stock [Line Items]
Redemption price per share	$ 1.86
Payments on redemption of preferred stock	$ 160.1
Minimum
Class of Stock [Line Items]
Percentage of beneficial ownership initially, after conversion		4.99%
Maximum
Class of Stock [Line Items]
Percentage of beneficial ownership thereafter, after conversion		19.99%

Organization and Operations - J

Organization and Operations - January 2020 Financing (Details) - January 2020 Financing $ / shares in Units, $ in Millions	1 Months Ended
	Jan. 31, 2020USD ($)$ / sharesshares
Class of Stock [Line Items]
Share price (in dollars per share) | $ / shares	$ 5
Gross proceeds from public offering | $	$ 26.5
Net proceeds from public offering | $	$ 24.6
Common Stock
Class of Stock [Line Items]
Number of shares issued | shares	5,290,000
Oppenheimer & Co. Inc
Class of Stock [Line Items]
Number of shares issued | shares	690,000

Organization and Operations - L

Organization and Operations - Liquidity (Details) - USD ($) $ / shares in Units, $ in Thousands	Jan. 28, 2021	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020	Jan. 31, 2020
Common Stock
Cash and cash equivalents		$ 146,920	$ 13,344	$ 24,930
Accumulated deficit		$ (430,981)		$ (260,897)
Common Stock, Par or Stated Value Per Share		$ 0.001		$ 0.001
January 2020 Financing
Common Stock
Share price (in dollars per share)					$ 5
Quellis Biosciences, Inc | Series X Preferred Stock
Common Stock
Shares issued on acquisition (in shares)		86,077
Common Stock
Common Stock
Shares issued on acquisition (in shares)		3,332,669
Issuance of common stock for at-the-market offerings (in shares)			173,572
Common Stock | ATM
Common Stock
Share price (in dollars per share)		$ 6.29
Issuance of common stock for at-the-market offerings (in shares)		173,572
Net proceeds		$ 1,100
Common Stock | Cowen
Common Stock
Percentage of commission paid to underwriter based on proceeds from common stock		3.00%
Common Stock, Par or Stated Value Per Share		$ 0.001
Common Stock | Quellis Biosciences, Inc
Common Stock
Shares issued on acquisition (in shares)	3,332,669
Number of shares issuable upon conversion of preferred stock		86,077,000
Share price (in dollars per share)	$ 0.001

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Net Loss Per Share (Details) - shares	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Antidilutive common stock equivalents excluded from computation of diluted net loss per share
Anti-dilutive securities excluded from the calculation of diluted net loss per share (in shares)	96,892,207	7,400,393
Series X Preferred Stock
Antidilutive common stock equivalents excluded from computation of diluted net loss per share
Anti-dilutive securities excluded from the calculation of diluted net loss per share (in shares)	86,077,000
Stock options
Antidilutive common stock equivalents excluded from computation of diluted net loss per share
Anti-dilutive securities excluded from the calculation of diluted net loss per share (in shares)	1,631,322	1,206,644
Common stock warrants
Antidilutive common stock equivalents excluded from computation of diluted net loss per share
Anti-dilutive securities excluded from the calculation of diluted net loss per share (in shares)	6,378,885	6,193,749
Preferred stock warrants
Antidilutive common stock equivalents excluded from computation of diluted net loss per share
Anti-dilutive securities excluded from the calculation of diluted net loss per share (in shares)	2,805,000

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Cash, Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020	Mar. 31, 2020	Dec. 31, 2019
Summary of Significant Accounting Policies
Cash and cash equivalents	$ 146,920	$ 24,930	$ 13,344
Restricted cash (1)	121		235
Total	$ 147,041	$ 25,051	$ 13,579	$ 10,376

Acquisition of Quellis (Details

Acquisition of Quellis (Details) - USD ($)	Jan. 28, 2021	Mar. 31, 2021
Business Acquisition [Line Items]
Convertible preferred stock shares issued upon conversion		1,000
Common Stock
Business Acquisition [Line Items]
Number of shares issued as consideration		$ 3,000
Quellis Biosciences, Inc
Business Acquisition [Line Items]
Cost to acquire the assets	$ 170,681,000
Acquisition costs	1,800,000
Quellis Biosciences, Inc | Common Stock
Business Acquisition [Line Items]
Number of shares issued as consideration	$ 3,332,669
Convertible preferred stock shares issued upon conversion	1,000
Series X Preferred Stock
Business Acquisition [Line Items]
Convertible preferred stock shares issued upon conversion		1,000
Series X Preferred Stock | Quellis Biosciences, Inc
Business Acquisition [Line Items]
Number of shares issued as consideration	$ 50,504

Acquisition of Quellis - Net as

Acquisition of Quellis - Net assets acquired based on their estimated fair values (Details) - Quellis Biosciences, Inc $ in Thousands	Jan. 28, 2021USD ($)
Business Acquisition [Line Items]
Acquired IPR&D	$ 164,612
Cash and cash equivalents	8,307
Prepaid expenses and other assets	136
Accounts payable	(1,974)
Accrued liabilities	(400)
Net acquired tangible assets	$ 170,681

Financial Instruments (Details)

Financial Instruments (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Financial Instruments
Fair value assets, transfers from Level 1 to Level 2	$ 0	$ 0
Fair value assets, transfers from Level 2 to Level 1	0	0
Fair value liabilities, transfers from Level 1 to Level 2	0	0
Fair value liabilities, transfers from Level 2 to Level 1	$ 0	0
Reverse repurchase agreements | Government Securities and Obligations | Minimum
Financial Instruments
Percentage of investment amount to collateralized deposits value	102.00%
Recurring
Assets:
Total assets	$ 40,833	42,999
Liabilities:
Warrant liability	4,369
Total liabilities	4,369
Recurring | Level 1
Assets:
Total assets	1,833	22,999
Recurring | Level 2
Assets:
Total assets	39,000	20,000
Recurring | Level 3
Liabilities:
Warrant liability	4,369
Total liabilities	4,369
Recurring | Money market fund
Assets:
Cash and cash equivalents	1,833	22,999
Recurring | Money market fund | Level 1
Assets:
Cash and cash equivalents	1,833	22,999
Recurring | Reverse repurchase agreements
Assets:
Cash and cash equivalents	39,000
Short-term investments		20,000
Recurring | Reverse repurchase agreements | Level 2
Assets:
Cash and cash equivalents	$ 39,000
Short-term investments		$ 20,000

Financial Instruments - fair va

Financial Instruments - fair value hierarchy (Details) - Derivative warrant liability $ in Thousands	3 Months Ended
	Mar. 31, 2021USD ($)
Derivative warrant liability was valued based on significant inputs not observable in the market, which represents a Level 3
Beginning balance	$ 0
Issuance of liability classified warrants	4,332
Change in fair value and current period expense	37
Ending balance	$ 4,369

Short-Term Investments (Details

Short-Term Investments (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020USD ($)instrument
Short-Term Investments
Amortized Cost	$ 20,000
Fair Value	$ 20,000
Number of short term investments in unrealized loss position | instrument	0
Reverse repurchase agreements
Short-Term Investments
Amortized Cost	$ 20,000
Fair Value	$ 20,000

Accrued Expenses (Details)

Accrued Expenses (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Accrued Expenses
Accrued compensation	$ 704	$ 1,719
Accrued other	384
Accrued professional fees	371	356
Accrued severance	205	396
Accrued contracted research costs	281	1,726
Total	$ 1,945	$ 4,197

Stockholders' Equity - Preferre

Stockholders' Equity - Preferred Stock (Details)	Mar. 31, 2021series$ / sharesshares	Feb. 28, 2021shares
Preferred Stock
Preferred stock, authorized (in shares)	5,000,000
Preferred stock, par value (in dollars per share) | $ / shares	$ 0.001
Preferred stock, outstanding (in shares)	86,077
Minimum number of series used to issue preferred stock | series	1
Series X Preferred Stock
Preferred Stock
Preferred stock, outstanding (in shares)	86,077	88,882
Exercise price of warrants (in dollars per share) | $ / shares	$ 341.17

Stockholders' Equity - Common S

Stockholders' Equity - Common Stock Warrants (Details)	3 Months Ended
	Mar. 31, 2021USD ($)$ / sharesshares
Common Stock Warrants
Warrants exercisable | $	$ 2,805
Common stock warrants
Common Stock Warrants
Warrants Outstanding (in shares) | shares	9,183,885
Common stock warrants | Weighted Average
Common Stock Warrants
Exercise Price (in dollars per share)	$ 6.99
Weighted average life (in years)	4 years 9 months 18 days
Series X Preferred Stock
Common Stock Warrants
Exercise Price (in dollars per share)	$ 341.17
Warrants exercisable | $	$ 2,805
Warrants Issued in 2014 | Common stock warrants
Common Stock Warrants
Warrants Outstanding (in shares) | shares	1,227
Exercise Price (in dollars per share)	$ 122.12
Warrants Issued in 2015 | Common stock warrants
Common Stock Warrants
Warrants Outstanding (in shares) | shares	1,227
Exercise Price (in dollars per share)	$ 122.12
Warrants Issued in 2018 | Common stock warrants
Common Stock Warrants
Warrants Outstanding (in shares) | shares	4,199,995
Exercise Price (in dollars per share)	$ 12
Warrants Issued in 2019 | Common stock warrants
Common Stock Warrants
Warrants Outstanding (in shares) | shares	1,991,300
Exercise Price (in dollars per share)	$ 6.25
Warrants Issued In 2021 | Common stock warrants
Common Stock Warrants
Warrants Outstanding (in shares) | shares	185,136
Exercise Price (in dollars per share)	$ 0.35
Warrants Issued In 2021 | Series X Preferred Stock
Common Stock Warrants
Warrants Outstanding (in shares) | shares	2,805,000
Exercise Price (in dollars per share)	$ 0.34

Reserved for Future Issuance (D

Reserved for Future Issuance (Details) - USD ($)	Mar. 31, 2021	Dec. 31, 2020
Common Stock
Number of shares reserved for future issuance	10,191,950	9,646,540
Preferred stock, outstanding (in shares)	86,077
Warrants outstanding (in shares)	$ 2,805
Convertible preferred stock shares issued upon conversion	1,000
Common stock warrants
Common Stock
Number of shares reserved for future issuance	6,378,885	6,193,749
Options outstanding to purchase Common Stock
Common Stock
Number of shares reserved for future issuance	1,631,322	1,367,667
Options available for future issuance to purchase Common Stock
Common Stock
Number of shares reserved for future issuance	1,996,322	1,936,173
Shares reserved for the employee stock purchase plan
Common Stock
Number of shares reserved for future issuance	185,421	148,951

Stock Incentive Plans (Details)

Stock Incentive Plans (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Shares
Outstanding, beginning of period (in shares)	1,367,667
Granted (in shares)	30,000
Assumed in Quellis Acquisition (in shares)	332,494
Cancelled or forfeited (in shares)	(90,164)
Expired (in shares)	(8,675)
Outstanding, end of period (in shares)	1,631,322		1,367,667
Vested and exercisable (in shares)	622,533
Weighted-Average Exercise Price
Outstanding, beginning of period (in dollars per share)	$ 11.38
Granted (in dollars per share)	2.43
Assumed in Quellis Acquisition (in dollars per share)	0.29
Cancelled or forfeited (in dollars per share)	16.70
Expired (in dollars per share)	9.16
Outstanding at end of year (in dollars per share)	17.83		$ 11.38
Vested and Exercisable (in dollars per share)	$ 9.16
Weighted Average Remaining Contractual Term (years)
Outstanding	8 years 3 months		8 years 1 month 17 days
Vested and Exercisable	7 years
Aggregate Intrinsic Value
Outstanding	$ 879
Stock options
Stock Incentive Plans
Exercised (in shares)	0	0
Aggregate fair value of options vested	$ 500	$ 400
Weighted average grant date fair value of options granted (in dollars per share)	$ 1.50	$ 3.57
Unrecognized compensation expense related to unvested stock option awards	$ 2,800
Weighted-average amortization period over which cost is expected to be recognized	2 years 2 months 12 days