Editas Medicine (EDIT) 10-Q 6 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
Document Type	10-Q
Document Quarterly Report	true
Document Transition Report	false
Document Period End Date	Mar. 31, 2021
Entity File Number	001-37687
Entity Registrant Name	EDITAS MEDICINE, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	46-4097528
Entity Address, Address Line One	11 Hurley Street
Entity Address, City or Town	Cambridge
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02141
City Area Code	617
Local Phone Number	401-9000
Title of 12(b) Security	Common Stock
Trading Symbol	EDIT
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		67,826,436
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q1
Entity Central Index Key	0001650664
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	$ 354,918	$ 139,682
Marketable securities	270,415	262,428
Accounts receivable	672	6,048
Prepaid expenses and other current assets	6,311	10,929
Total current assets	632,316	419,087
Marketable securities	97,890	109,664
Property and equipment, net	14,095	14,020
Right-of-use assets	29,305	25,128
Restricted cash and other non-current assets	6,688	4,703
Total assets	780,294	572,602
Current liabilities:
Accounts payable	8,910	6,408
Accrued expenses	15,132	24,046
Deferred revenue, current	32,704	20,943
Operating lease liabilities	7,264	6,811
Total current liabilities	64,010	58,208
Operating lease liabilities, net of current portion	21,621	19,324
Deferred revenue, net of current portion	56,667	73,984
Other non-current liabilities		27,500
Total liabilities	142,298	179,016
Stockholders' equity
Preferred stock, $0.0001 par value per share: 5,000,000 shares authorized; no shares issued or outstanding
Common stock, $0.0001 par value per share: 195,000,0000 shares authorized; 67,580,615 and 62,689,457 shares issued, and 67,472,615 and 62,563,457 shares outstanding at March 31, 2021 and December 31, 2020, respectively	7	6
Additional paid-in capital	1,359,987	1,058,823
Accumulated other comprehensive loss	(73)	(46)
Accumulated deficit	(721,925)	(665,197)
Total stockholders' equity	637,996	393,586
Total liabilities and stockholders' equity	$ 780,294	$ 572,602

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Mar. 31, 2021	Dec. 31, 2020
Condensed Consolidated Balance Sheets
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized	195,000,000	195,000,000
Common stock, shares issued	67,580,615	62,689,457
Common stock, shares outstanding	67,472,615	62,563,457

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Condensed Consolidated Statements of Operations
Collaboration and other research and development revenues	$ 6,499	$ 5,723
Revenue type	us-gaap:ServiceMember	us-gaap:ServiceMember
Operating expenses:
Research and development	$ 41,937	$ 34,570
General and administrative	21,445	17,769
Total operating expenses	63,382	52,339
Operating loss	(56,883)	(46,616)
Other income, net:
Other income, net	21	7,333
Interest income, net	134	1,559
Total other income, net	155	8,892
Net loss	$ (56,728)	$ (37,724)
Net loss per share, basic and diluted	$ (0.86)	$ (0.69)
Weighted-average common shares outstanding, basic (in shares)	65,992,395	54,590,194

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	$ (56,728)	$ (37,724)
Other comprehensive (loss) income:
Unrealized (loss) gain on marketable debt securities	(27)	587
Comprehensive loss	$ (56,755)	$ (37,137)

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Common Stock	Additional Paid-In Capital	Accumulated Deficit	Accumulated Other Comprehensive (Loss) Income	Total
Balance, beginning of period at Dec. 31, 2019	$ 5	$ 811,546	$ (549,221)	$ 107	$ 262,437
Balance, beginning of period (in shares) at Dec. 31, 2019	54,355,798
Statement of Stockholders' Equity (Deficit)
Exercise of stock options		3,047			3,047
Exercise of stock options (in shares)	233,208
Stock-based compensation expense		6,220			6,220
Vesting of restricted common stock awards (in shares)	213,393
Unrealized gain (loss) on marketable debt securities				587	587
Net loss			(37,724)		(37,724)
Balance, end of period at Mar. 31, 2020	$ 5	820,813	(586,945)	694	234,567
Balance, end of period (in shares) at Mar. 31, 2020	54,802,399
Balance, beginning of period at Dec. 31, 2020	$ 6	1,058,823	(665,197)	(46)	393,586
Balance, beginning of period (in shares) at Dec. 31, 2020	62,563,457
Statement of Stockholders' Equity (Deficit)
Issuance of common stock for public offering	$ 1	249,458			249,459
Issuance of common stock for public offering (in shares)	4,025,000
Issuance of common stock for success payment		27,500			27,500
Issuance of common stock for success payment (in shares)	303,599
Exercise of stock options		12,002			12,002
Exercise of stock options (in shares)	501,162
Stock-based compensation expense		12,204			12,204
Vesting of restricted common stock awards (in shares)	79,397
Unrealized gain (loss) on marketable debt securities				(27)	(27)
Net loss			(56,728)		(56,728)
Balance, end of period at Mar. 31, 2021	$ 7	$ 1,359,987	$ (721,925)	$ (73)	$ 637,996
Balance, end of period (in shares) at Mar. 31, 2021	67,472,615

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Cash flow from operating activities
Net loss	$ (56,728)	$ (37,724)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	12,204	6,220
Depreciation	1,163	798
Unrealized gain on corporate equity securities		7,333
Other non-cash items, net	401	(215)
Changes in operating assets and liabilities:
Accounts receivable	5,376	(1,414)
Prepaid expenses and other current assets	4,618	(1,995)
Right-of-use assets	(4,177)	1,739
Other non-current assets	(1,985)	93
Accounts payable	2,017	4,767
Accrued expenses	(9,563)	(13,644)
Deferred revenue	(5,555)	(4,309)
Operating lease liabilities	2,750	(1,902)
Other current and non-current liabilities		833
Net cash used in operating activities	(49,479)	(54,086)
Cash flow from investing activities
Purchases of property and equipment	(84)	(2,152)
Purchases of marketable securities	(127,422)	(66,384)
Proceeds from maturities of marketable securities	130,750	115,000
Net cash provided by investing activities	3,244	46,464
Cash flow from financing activities
Proceeds from offering of common stock, net of issuance costs	249,469
Proceeds from exercise of stock options	12,002	3,047
Net cash provided by financing activities	261,471	3,047
Net increase (decrease) in cash, cash equivalents, and restricted cash	215,236	(4,575)
Cash, cash equivalents, and restricted cash, beginning of period	143,559	239,802	$ 239,802
Cash, cash equivalents, and restricted cash, end of period	358,795	235,227	$ 143,559
Supplemental disclosure of cash and non-cash activities:
Fixed asset additions included in accounts payable and accrued expenses	467	705
Cash paid in connection with operating lease liabilities	4,248	$ 2,538
Offering costs included in accounts payable and accrued expenses	10
Issuance of common stock for settlement of success payments	$ 27,500

Nature of Business

Nature of Business	3 Months Ended
	Mar. 31, 2021
Nature of Business
Nature of Business	1. Nature of Business ​ Editas Medicine, Inc. (the “Company”) is a leading, clinical stage genome editing company dedicated to developing potentially transformative genomic medicines to treat a broad range of serious diseases. The Company was incorporated in the state of Delaware in September 2013. Its principal offices are in Cambridge, Massachusetts. Since its inception, the Company has devoted substantially all of its efforts to business planning, research and development, recruiting management and technical staff, and raising capital. The Company has primarily financed its operations through various equity financings, payments received under a research collaboration with Juno Therapeutics, a wholly-owned subsidiary of the Bristol-Myers Squibb Company (“Juno Therapeutics”), payments received under a strategic alliance and option agreement with Allergan Pharmaceuticals International Limited (together with its affiliates, “Allergan”) , which was terminated in August 2020, and its license agreement with Beam Therapeutics. 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 and ability to transition from pilot-scale manufacturing to large-scale production of products. Liquidity ​ In January 2021, the Company completed a public offering whereby it sold 3,500,000 shares of its common stock and received net proceeds of approximately $216.9 million. In February 2021, the underwriters in the public offering exercised their option to purchase an additional 525,000 shares, resulting in additional net proceeds to the Company of approximately $32.6 million. ​ The Company has incurred annual net operating losses in every year since its inception. The Company expects that its existing cash, cash equivalents and marketable securities at March 31, 2021 and anticipated interest income will enable it to fund its operating expenses and capital expenditure requirements well into 2023 . The Company had an accumulated deficit of $721.9 million at March 31, 2021, and will require substantial additional capital to fund its operations. The Company has never generated any product revenue. There can be no assurance that the Company will be able to obtain additional debt or equity 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.

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 ​ Unaudited Interim Financial Information ​ The condensed consolidated financial statements of the Company included herein have been prepared, without audit, pursuant to the rules and regulations of the Securities and Exchange Commission (the “SEC”). Certain information and footnote disclosures normally included in financial statements prepared in accordance with generally accepted accounting principles in the United States of America (“GAAP”) have been condensed or omitted from this report, as is permitted by such rules and regulations. Accordingly, these condensed consolidated financial statements should be read in conjunction with the financial statements and notes thereto included in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2020 (the “Annual Report”). ​ The unaudited condensed consolidated financial statements include the accounts of the Company and its wholly owned subsidiary, Editas Securities Corporation. All intercompany transactions and balances of the subsidiary have been eliminated in consolidation. In the opinion of management, the information furnished reflects all adjustments, all of which are of a normal and recurring nature, necessary for a fair presentation of the results for the reported interim periods. The Company considers events or transactions that occur after the balance sheet date but before the financial statements are issued to provide additional evidence relative to certain estimates or to identify matters that require additional disclosure. The three months ended March 31, 2021 and 2020 are referred to as the first quarter of 2021 and 2020, respectively. The results of operations for interim periods are not necessarily indicative of results to be expected for the full year or any other interim period. ​ Summary of Significant Accounting Policies ​ The Company’s significant accounting policies are described in Note 2, “Summary of significant accounting policies,” to the consolidated financial statements included in the Annual Report. There have been no material changes to the significant accounting policies previously disclosed in the Annual Report. ​ ​

Cash Equivalents and Marketable

Cash Equivalents and Marketable Securities	3 Months Ended
	Mar. 31, 2021
Cash Equivalents and Marketable Securities
Cash Equivalents and Marketable Securities	3. Cash Equivalents and Marketable Securities ​ Cash equivalents and marketable securities consisted of the following at March 31, 2021 (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Allowance ​ ​ Gross ​ Gross ​ ​ ​ ​ Amortized ​ for Credit ​ ​ Unrealized ​ Unrealized ​ Fair March 31, 2021 ​ Cost ​ Losses ​ ​ Gains ​ Losses ​ Value Cash equivalents and marketable securities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Money market funds ​ $ 344,918 ​ $ — ​ ​ $ — ​ $ — ​ $ 344,918 U.S. Treasuries ​ ​ 81,255 ​ ​ — ​ ​ ​ 7 ​ ​ (2) ​ ​ 81,260 Government agency securities ​ ​ 154,022 ​ ​ — ​ ​ ​ 7 ​ ​ (41) ​ ​ 153,988 Corporate notes/bonds ​ ​ 50,249 ​ ​ — ​ ​ ​ — ​ ​ (41) ​ ​ 50,208 Commercial Paper ​ ​ 92,852 ​ ​ — ​ ​ ​ 1 ​ ​ (4) ​ ​ 92,849 Total ​ $ 723,296 ​ $ — ​ ​ $ 15 ​ $ (88) ​ $ 723,223 ​ Cash equivalents and marketable securities consisted of the following at December 31, 2020 (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Allowance ​ ​ Gross ​ Gross ​ ​ ​ ​ Amortized ​ for Credit ​ ​ Unrealized ​ Unrealized ​ Fair December 31, 2020 ​ Cost ​ Losses ​ ​ Gains ​ Losses ​ Value Cash equivalents and marketable securities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Money market funds ​ $ 139,682 ​ $ — ​ ​ $ — ​ $ — ​ $ 139,682 U.S. Treasuries ​ ​ 180,376 ​ ​ — ​ ​ ​ 8 ​ ​ (11) ​ ​ 180,373 Government agency securities ​ ​ 107,665 ​ ​ — ​ ​ ​ — ​ ​ (20) ​ ​ 107,645 Commercial paper ​ ​ 41,912 ​ ​ — ​ ​ ​ — ​ ​ (8) ​ ​ 41,904 Corporate notes/bonds ​ ​ 42,185 ​ ​ — ​ ​ ​ 10 ​ ​ (25) ​ ​ 42,170 Total ​ $ 511,820 ​ $ — ​ ​ $ 18 ​ $ (64) ​ $ 511,774 ​ As of March 31, 2021, the Company did not hold any marketable securities that had been in an unrealized loss position for more than twelve months. Furthermore, the Company has determined that there were no material changes in the credit risk of the debt securities. As of March 31, 2021, the Company holds 44 securities with an aggregate fair value of $97.9 million that had remaining maturities between one and two years. ​ There were no realized gains or losses on available-for-sale securities during the three months ended March 31, 2021 or 2020.

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2021
Fair Value Measurements
Fair Value Measurements	4. Fair Value Measurements ​ Assets measured at fair value on a recurring basis as of March 31, 2021 were as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Quoted Prices Significant ​ ​ ​ ​ ​ ​ ​ in Active ​ Other ​ Significant ​ ​ ​ ​ ​ Markets for ​ Observable ​ Unobservable ​ ​ March 31, ​ Identical Assets ​ Inputs ​ Inputs Financial Assets ​ 2021 ​ (Level 1) ​ (Level 2) ​ (Level 3) Cash equivalents: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Money market funds ​ $ 344,918 ​ $ 344,918 ​ $ — ​ $ — Marketable securities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. Treasuries ​ ​ 81,260 ​ ​ 81,260 ​ ​ — ​ ​ — Government agency securities ​ ​ 153,988 ​ ​ — ​ ​ 153,988 ​ ​ — Commercial paper ​ ​ 92,849 ​ ​ — ​ ​ 92,849 ​ ​ — Corporate notes/bonds ​ ​ 50,208 ​ ​ — ​ ​ 50,208 ​ ​ — Restricted cash and other non-current assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Money market funds ​ ​ 3,877 ​ ​ 3,877 ​ ​ — ​ ​ — Total financial assets ​ $ 727,100 ​ $ 430,055 ​ $ 297,045 ​ $ — ​ Assets measured at fair value on a recurring basis as of December 31, 2020 were as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Quoted Prices Significant ​ ​ ​ ​ ​ ​ ​ in Active ​ Other ​ Significant ​ ​ ​ ​ ​ Markets for ​ Observable ​ Unobservable ​ ​ December 31, ​ Identical Assets ​ Inputs ​ Inputs Financial Assets ​ 2020 ​ (Level 1) ​ (Level 2) ​ (Level 3) Cash equivalents: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Money market funds ​ $ 139,682 ​ $ 139,682 ​ $ — ​ $ — Marketable securities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. Treasuries ​ ​ 180,373 ​ ​ 180,373 ​ ​ — ​ ​ — Government agency securities ​ ​ 107,645 ​ ​ — ​ ​ 107,645 ​ ​ — Commercial paper ​ ​ 41,904 ​ ​ — ​ ​ 41,904 ​ ​ ​ Corporate bonds ​ ​ 42,170 ​ ​ — ​ ​ 42,170 ​ ​ ​ Restricted cash and other non-current assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Money market funds ​ ​ 3,877 ​ ​ 3,877 ​ ​ — ​ ​ — Total financial assets ​ $ 515,651 ​ $ 323,932 ​ $ 191,719 ​ $ — ​

Accrued Expenses

Accrued Expenses	3 Months Ended
	Mar. 31, 2021
Accrued Expenses
Accrued Expenses	5. Accrued Expenses ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of ​ ​ March 31, ​ December 31, ​ 2021 2020 External research and development expenses ​ $ 6,795 ​ $ 12,820 Employee related expenses ​ ​ 4,439 ​ 5,323 Intellectual property and patent related fees ​ ​ 2,320 ​ ​ 4,240 Professional service expenses ​ ​ 660 ​ ​ 533 Other expenses ​ ​ 505 ​ ​ 359 Sublicensing expenses ​ ​ 413 ​ ​ 771 Total accrued expenses ​ $ 15,132 ​ $ 24,046 ​ ​ ​ ​ ​ ​ ​ ​

Property and Equipment, net

Property and Equipment, net	3 Months Ended
	Mar. 31, 2021
Property and Equipment, net
Property and Equipment, net	6. Property and Equipment, net ​ Property and equipment, net consisted of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ As of ​ ​ March 31, ​ December 31, ​ 2021 2020 Laboratory equipment ​ $ 18,282 ​ $ 18,433 Leasehold improvements ​ ​ 5,341 ​ ​ 4,967 Construction-in-progress ​ 1,245 ​ 500 Computer equipment ​ ​ 858 ​ ​ 858 Furniture and office equipment ​ ​ 239 ​ ​ 239 Software ​ 118 ​ 118 Total property and equipment ​ 26,083 ​ 25,115 Less: accumulated depreciation ​ (11,988) ​ (11,095) Property and equipment, net ​ $ 14,095 ​ $ 14,020 ​

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2021
Commitments and Contingencies
Commitments and Contingencies	7. Commitments and Contingencies ​ ​ Licensor Expense Reimbursement ​ The Company is obligated to reimburse The Broad Institute, Inc. (“Broad”) and the President and Fellows of Harvard College (“Harvard”) for expenses incurred by each of them associated with the prosecution and maintenance of the patent rights that the Company licenses from them pursuant to the license agreement by and among the Company, Broad and Harvard, including the interference and opposition proceedings involving patents licensed to the Company under the license agreement, and other license agreements between the Company and Broad. As such, the Company anticipates that it has a substantial commitment in connection with these proceedings until such time as these proceedings have been resolved, but the amount of such commitment is not determinable. The Company incurred an aggregate of $3.8 million in expense during both the three months ended March 31, 2021 and 2020 for such reimbursement.

Collaboration and Profit-Sharin

Collaboration and Profit-Sharing Agreements	3 Months Ended
	Mar. 31, 2021
Collaboration and Profit-Sharing Agreements
Collaboration and Profit-Sharing Agreements	8 Collaboration and Profit-Sharing Agreements ​ The Company has entered into multiple collaborations, out-licenses and strategic alliances with third parties that typically involve payments to or from the Company, including up-front payments, payments for research and development services, option payments, milestone payments and royalty payments to or from the Company. The terms and conditions as well as the accounting analysis for the Company’s significant collaborations, out-licenses and strategic alliances are described in Note 9, “Collaboration and Profit-Sharing Agreements” to the consolidated financial statements included in the Annual Report. There have been no material changes to the terms and conditions, or the accounting conclusions previously disclosed in the Annual Report. ​ Collaboration Revenue ​ As of March 31, 2021, the Company’s contract liabilities were primarily related to the Company’s collaboration with Juno Therapeutics. The following table presents changes in the Company’s accounts receivable and contract liabilities for the three months ended March 31, 2021 (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the three months ended March 31, 2021 Balance at December 31, 2020 ​ Additions ​ Deductions ​ Balance at March 31, 2021 Accounts receivable $ 6,048 ​ $ 316 ​ $ (5,692) ​ $ 672 Contract liabilities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Deferred revenue $ 94,927 ​ $ 150 ​ $ (5,706) ​ $ 89,371 ​ During the three months ended March 31, 2021, the Company recognized the following collaboration revenue (in thousands): ​ ​ ​ ​ Three Months Ended Revenue recognized in the period from: March 31, 2021 Amounts included in deferred revenue at the beginning of the period $ 5,706 Performance obligations satisfied in previous periods $ — ​

Stock-Based Compensation

Stock-Based Compensation	3 Months Ended
	Mar. 31, 2021
Stock-Based Compensation
Stock-Based Compensation	9 Stock-based Compensation ​ Total compensation cost recognized for all stock-based compensation awards in the condensed consolidated statements of operations was as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ ​ March 31, ​ ​ 2021 ​ 2020 Research and development ​ $ 3,966 ​ $ 3,057 General and administrative ​ 8,238 ​ 3,163 Total stock-based compensation expense ​ $ 12,204 ​ $ 6,220 ​ Restricted Stock and Restricted Stock Unit Awards ​ The following is a summary of restricted stock and restricted stock unit awards activity for the three months ended March 31, 2021: ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ ​ ​ Average ​ ​ ​ ​ Grant Date ​ ​ ​ ​ Fair Value ​ ​ Shares ​ Per Share Unvested restricted stock and restricted stock unit awards as of December 31, 2020 507,450 ​ $ 27.35 Issued 424,017 ​ $ 52.49 Vested (79,397) ​ $ 27.48 Forfeited ​ (54,036) ​ $ 32.69 Unvested restricted stock and restricted stock unit awards as of March 31, 2021 798,034 ​ $ 40.94 ​ As of March 31, 2021, total unrecognized compensation expense related to unvested restricted stock and restricted stock unit awards was $24.8 million, which the Company expects to recognize over a remaining weighted-average period of 2.5 years. ​ Stock Options ​ The following is a summary of stock option activity for the three months ended March 31, 2021: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted Average Remaining Aggregate Intrinsic ​ ​ Shares ​ Exercise Price ​ Contractual Life (years) ​ Value (in thousands) Outstanding at December 31, 2020 3,912,257 ​ $ 27.26 ​ 7.9 ​ $ 167,640 Granted ​ 913,803 ​ $ 46.42 ​ ​ ​ ​ ​ Exercised ​ (501,162) ​ $ 23.95 ​ ​ ​ ​ ​ Cancelled ​ (488,579) ​ $ 28.19 ​ ​ ​ ​ ​ Outstanding at March 31, 2021 3,836,319 ​ $ 32.14 ​ 7.1 ​ $ 43,349 Exercisable at March 31, 2021 1,503,421 ​ $ 25.21 ​ 4.3 ​ $ 25,238 ​ As of March 31, 2021, total unrecognized compensation expense related to stock options was $41.6 million, which the Company expects to recognize over a remaining weighted-average period of 2.6 years.

Net Income (Loss) per Share

Net Income (Loss) per Share	3 Months Ended
	Mar. 31, 2021
Net Income (Loss) per Share
Net Income (Loss) per Share	10. Net Loss per Share ​ Basic net loss per common share is calculated by dividing the net loss attributable to common stockholders by the weighted average number of shares of common stock outstanding during the period, without consideration for potentially dilutive securities. Diluted net loss per share is computed by dividing the net loss attributable to common stockholders by the weighted average number of shares of common stock and potentially dilutive securities outstanding for the period determined using the treasury stock and if converted methods. Contingently issuable shares are included in the calculation of basic loss per share as of the beginning of the period in which all the necessary conditions have been satisfied. Contingently issuable shares are included in diluted loss per share based on the number of shares, if any, that would be issuable under the terms of the arrangement if the end of the reporting period was the end of the contingency period, if the results are dilutive. ​ For purposes of the diluted net loss per share calculation, stock options are considered to be common stock equivalents, but they were excluded from the Company’s calculation of diluted net loss per share allocable to common stockholders because their inclusion would have been anti-dilutive. Therefore, basic and diluted net loss per share applicable to common stockholders were the same for all periods presented. ​ The following common stock equivalents were excluded from the calculation of diluted net loss per share allocable to common stockholders because their inclusion would have been anti-dilutive: ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ ​ ​ March 31, ​ ​ 2021 ​ 2020 ​ Unvested restricted stock and restricted stock unit awards 798,034 ​ 638,054 ​ Outstanding stock options 3,836,319 ​ 4,862,947 ​ Total 4,634,353 ​ 5,501,001 ​ ​

Cash Equivalents and Marketab_2

Cash Equivalents and Marketable Securities (Tables)	3 Months Ended
	Mar. 31, 2021
Cash Equivalents and Marketable Securities
Schedule of cash equivalents and marketable securities	Cash equivalents and marketable securities consisted of the following at March 31, 2021 (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Allowance ​ ​ Gross ​ Gross ​ ​ ​ ​ Amortized ​ for Credit ​ ​ Unrealized ​ Unrealized ​ Fair March 31, 2021 ​ Cost ​ Losses ​ ​ Gains ​ Losses ​ Value Cash equivalents and marketable securities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Money market funds ​ $ 344,918 ​ $ — ​ ​ $ — ​ $ — ​ $ 344,918 U.S. Treasuries ​ ​ 81,255 ​ ​ — ​ ​ ​ 7 ​ ​ (2) ​ ​ 81,260 Government agency securities ​ ​ 154,022 ​ ​ — ​ ​ ​ 7 ​ ​ (41) ​ ​ 153,988 Corporate notes/bonds ​ ​ 50,249 ​ ​ — ​ ​ ​ — ​ ​ (41) ​ ​ 50,208 Commercial Paper ​ ​ 92,852 ​ ​ — ​ ​ ​ 1 ​ ​ (4) ​ ​ 92,849 Total ​ $ 723,296 ​ $ — ​ ​ $ 15 ​ $ (88) ​ $ 723,223 ​ Cash equivalents and marketable securities consisted of the following at December 31, 2020 (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Allowance ​ ​ Gross ​ Gross ​ ​ ​ ​ Amortized ​ for Credit ​ ​ Unrealized ​ Unrealized ​ Fair December 31, 2020 ​ Cost ​ Losses ​ ​ Gains ​ Losses ​ Value Cash equivalents and marketable securities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Money market funds ​ $ 139,682 ​ $ — ​ ​ $ — ​ $ — ​ $ 139,682 U.S. Treasuries ​ ​ 180,376 ​ ​ — ​ ​ ​ 8 ​ ​ (11) ​ ​ 180,373 Government agency securities ​ ​ 107,665 ​ ​ — ​ ​ ​ — ​ ​ (20) ​ ​ 107,645 Commercial paper ​ ​ 41,912 ​ ​ — ​ ​ ​ — ​ ​ (8) ​ ​ 41,904 Corporate notes/bonds ​ ​ 42,185 ​ ​ — ​ ​ ​ 10 ​ ​ (25) ​ ​ 42,170 Total ​ $ 511,820 ​ $ — ​ ​ $ 18 ​ $ (64) ​ $ 511,774

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2021
Fair Value Measurements
Schedule of assets measured at fair value on a recurring basis	Assets measured at fair value on a recurring basis as of March 31, 2021 were as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Quoted Prices Significant ​ ​ ​ ​ ​ ​ ​ in Active ​ Other ​ Significant ​ ​ ​ ​ ​ Markets for ​ Observable ​ Unobservable ​ ​ March 31, ​ Identical Assets ​ Inputs ​ Inputs Financial Assets ​ 2021 ​ (Level 1) ​ (Level 2) ​ (Level 3) Cash equivalents: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Money market funds ​ $ 344,918 ​ $ 344,918 ​ $ — ​ $ — Marketable securities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. Treasuries ​ ​ 81,260 ​ ​ 81,260 ​ ​ — ​ ​ — Government agency securities ​ ​ 153,988 ​ ​ — ​ ​ 153,988 ​ ​ — Commercial paper ​ ​ 92,849 ​ ​ — ​ ​ 92,849 ​ ​ — Corporate notes/bonds ​ ​ 50,208 ​ ​ — ​ ​ 50,208 ​ ​ — Restricted cash and other non-current assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Money market funds ​ ​ 3,877 ​ ​ 3,877 ​ ​ — ​ ​ — Total financial assets ​ $ 727,100 ​ $ 430,055 ​ $ 297,045 ​ $ — ​ Assets measured at fair value on a recurring basis as of December 31, 2020 were as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Quoted Prices Significant ​ ​ ​ ​ ​ ​ ​ in Active ​ Other ​ Significant ​ ​ ​ ​ ​ Markets for ​ Observable ​ Unobservable ​ ​ December 31, ​ Identical Assets ​ Inputs ​ Inputs Financial Assets ​ 2020 ​ (Level 1) ​ (Level 2) ​ (Level 3) Cash equivalents: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Money market funds ​ $ 139,682 ​ $ 139,682 ​ $ — ​ $ — Marketable securities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. Treasuries ​ ​ 180,373 ​ ​ 180,373 ​ ​ — ​ ​ — Government agency securities ​ ​ 107,645 ​ ​ — ​ ​ 107,645 ​ ​ — Commercial paper ​ ​ 41,904 ​ ​ — ​ ​ 41,904 ​ ​ ​ Corporate bonds ​ ​ 42,170 ​ ​ — ​ ​ 42,170 ​ ​ ​ Restricted cash and other non-current assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Money market funds ​ ​ 3,877 ​ ​ 3,877 ​ ​ — ​ ​ — Total financial assets ​ $ 515,651 ​ $ 323,932 ​ $ 191,719 ​ $ —

Accrued Expenses (Tables)

Accrued Expenses (Tables)	3 Months Ended
	Mar. 31, 2021
Accrued Expenses
Schedule of accrued expenses	​ ​ ​ ​ ​ ​ ​ ​ ​ As of ​ ​ March 31, ​ December 31, ​ 2021 2020 External research and development expenses ​ $ 6,795 ​ $ 12,820 Employee related expenses ​ ​ 4,439 ​ 5,323 Intellectual property and patent related fees ​ ​ 2,320 ​ ​ 4,240 Professional service expenses ​ ​ 660 ​ ​ 533 Other expenses ​ ​ 505 ​ ​ 359 Sublicensing expenses ​ ​ 413 ​ ​ 771 Total accrued expenses ​ $ 15,132 ​ $ 24,046 ​ ​ ​ ​ ​ ​ ​

Property and Equipment, net (Ta

Property and Equipment, net (Tables)	3 Months Ended
	Mar. 31, 2021
Property and Equipment, net
Schedule of property and equipment, net	Property and equipment, net consisted of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ As of ​ ​ March 31, ​ December 31, ​ 2021 2020 Laboratory equipment ​ $ 18,282 ​ $ 18,433 Leasehold improvements ​ ​ 5,341 ​ ​ 4,967 Construction-in-progress ​ 1,245 ​ 500 Computer equipment ​ ​ 858 ​ ​ 858 Furniture and office equipment ​ ​ 239 ​ ​ 239 Software ​ 118 ​ 118 Total property and equipment ​ 26,083 ​ 25,115 Less: accumulated depreciation ​ (11,988) ​ (11,095) Property and equipment, net ​ $ 14,095 ​ $ 14,020

Collaboration and Profit-Shar_2

Collaboration and Profit-Sharing Agreements (Tables)	3 Months Ended
	Mar. 31, 2021
Collaboration and Profit-Sharing Agreements
Schedule of accounts receivable and contract liabilities	The following table presents changes in the Company’s accounts receivable and contract liabilities for the three months ended March 31, 2021 (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the three months ended March 31, 2021 Balance at December 31, 2020 ​ Additions ​ Deductions ​ Balance at March 31, 2021 Accounts receivable $ 6,048 ​ $ 316 ​ $ (5,692) ​ $ 672 Contract liabilities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Deferred revenue $ 94,927 ​ $ 150 ​ $ (5,706) ​ $ 89,371
Schedule of change in contract assets and contract liabilities	During the three months ended March 31, 2021, the Company recognized the following collaboration revenue (in thousands): ​ ​ ​ ​ Three Months Ended Revenue recognized in the period from: March 31, 2021 Amounts included in deferred revenue at the beginning of the period $ 5,706 Performance obligations satisfied in previous periods $ —

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2021
Stock-Based Compensation
Schedule of stock-based compensation expense	Total compensation cost recognized for all stock-based compensation awards in the condensed consolidated statements of operations was as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ ​ March 31, ​ ​ 2021 ​ 2020 Research and development ​ $ 3,966 ​ $ 3,057 General and administrative ​ 8,238 ​ 3,163 Total stock-based compensation expense ​ $ 12,204 ​ $ 6,220
Schedule of changes in unvested restricted stock	The following is a summary of restricted stock and restricted stock unit awards activity for the three months ended March 31, 2021: ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ ​ ​ Average ​ ​ ​ ​ Grant Date ​ ​ ​ ​ Fair Value ​ ​ Shares ​ Per Share Unvested restricted stock and restricted stock unit awards as of December 31, 2020 507,450 ​ $ 27.35 Issued 424,017 ​ $ 52.49 Vested (79,397) ​ $ 27.48 Forfeited ​ (54,036) ​ $ 32.69 Unvested restricted stock and restricted stock unit awards as of March 31, 2021 798,034 ​ $ 40.94
Schedule of stock option activity	The following is a summary of stock option activity for the three months ended March 31, 2021: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted Average Remaining Aggregate Intrinsic ​ ​ Shares ​ Exercise Price ​ Contractual Life (years) ​ Value (in thousands) Outstanding at December 31, 2020 3,912,257 ​ $ 27.26 ​ 7.9 ​ $ 167,640 Granted ​ 913,803 ​ $ 46.42 ​ ​ ​ ​ ​ Exercised ​ (501,162) ​ $ 23.95 ​ ​ ​ ​ ​ Cancelled ​ (488,579) ​ $ 28.19 ​ ​ ​ ​ ​ Outstanding at March 31, 2021 3,836,319 ​ $ 32.14 ​ 7.1 ​ $ 43,349 Exercisable at March 31, 2021 1,503,421 ​ $ 25.21 ​ 4.3 ​ $ 25,238

Net Income (Loss) per Share (Ta

Net Income (Loss) per Share (Tables)	3 Months Ended
	Mar. 31, 2021
Net Income (Loss) per Share
Schedule of anti-dilutive common stock equivalents	The following common stock equivalents were excluded from the calculation of diluted net loss per share allocable to common stockholders because their inclusion would have been anti-dilutive: ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ ​ ​ March 31, ​ ​ 2021 ​ 2020 ​ Unvested restricted stock and restricted stock unit awards 798,034 ​ 638,054 ​ Outstanding stock options 3,836,319 ​ 4,862,947 ​ Total 4,634,353 ​ 5,501,001 ​

Nature of Business (Details)

Nature of Business (Details) - USD ($) $ in Thousands	1 Months Ended		3 Months Ended
	Feb. 28, 2021	Jan. 31, 2021	Mar. 31, 2021	Dec. 31, 2020
Liquidity
Proceeds from offering of common stock, net of issuance costs			$ 249,469
Accumulated deficit			$ 721,925	$ 665,197
Public Offering
Liquidity
Number of common stock issued		3,500,000
Aggregate net proceeds		$ 216,900
Overallotment Option
Liquidity
Number of common stock issued	525,000
Aggregate net proceeds	$ 32,600

Cash Equivalents and Marketab_3

Cash Equivalents and Marketable Securities (Details) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2021USD ($)securityitem	Mar. 31, 2020USD ($)	Dec. 31, 2020USD ($)
Cash Equivalents and Marketable Securities
Amortized Cost	$ 723,296		$ 511,820
Gross Unrealized Gains	15		18
Gross Unrealized Losses	(88)		(64)
Fair Value	$ 723,223		511,774
Equity securities included in other non-current assets:
Gross Unrealized Gains		$ 7,333
Number of securities in an unrealized loss position for more than 12 months | item	0
Number of noncurrent securities | security	44
Noncurrent marketable securities	$ 97,890		109,664
Realized gains (losses) on available-for-sale securities	0	$ 0
U.S. Treasuries
Cash Equivalents and Marketable Securities
Amortized Cost	81,255		180,376
Gross Unrealized Gains	7		8
Gross Unrealized Losses	(2)		(11)
Fair Value	81,260		180,373
Government agency securities
Cash Equivalents and Marketable Securities
Amortized Cost	154,022		107,665
Gross Unrealized Gains	7
Gross Unrealized Losses	(41)		(20)
Fair Value	153,988		107,645
Corporate notes/bonds
Cash Equivalents and Marketable Securities
Amortized Cost	50,249
Gross Unrealized Losses	(41)
Fair Value	50,208
Equity securities included in other non-current assets:
Amortized Cost			42,185
Gross Unrealized Gains			10
Gross Unrealized Losses			(25)
Fair Value			42,170
Commercial paper
Cash Equivalents and Marketable Securities
Amortized Cost	92,852		41,912
Gross Unrealized Gains	1
Gross Unrealized Losses	(4)		(8)
Fair Value	92,849		41,904
Money market funds
Cash Equivalents and Marketable Securities
Amortized Cost	344,918		139,682
Fair Value	$ 344,918		$ 139,682

Fair Value Measurements - Recur

Fair Value Measurements - Recurring Basis (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Financial Assets
Marketable securities	$ 723,223	$ 511,774
U.S. Treasuries
Financial Assets
Marketable securities	81,260	180,373
Commercial paper
Financial Assets
Marketable securities	92,849	41,904
Corporate notes/bonds
Financial Assets
Equity securities		42,185
Marketable securities	50,208
Money market funds
Financial Assets
Marketable securities	344,918	139,682
Recurring
Financial Assets
Total financial assets	727,100	515,651
Recurring | U.S. Treasuries
Financial Assets
Marketable securities	81,260	180,373
Recurring | Government agency securities
Financial Assets
Marketable securities	153,988	107,645
Recurring | Commercial paper
Financial Assets
Marketable securities	92,849	41,904
Recurring | Corporate notes/bonds
Financial Assets
Marketable securities	50,208	42,170
Recurring | Money market funds
Financial Assets
Cash and cash equivalents	344,918	139,682
Recurring | Level 1
Financial Assets
Total financial assets	430,055	323,932
Recurring | Level 1 | U.S. Treasuries
Financial Assets
Marketable securities	81,260	180,373
Recurring | Level 1 | Money market funds
Financial Assets
Cash and cash equivalents	344,918	139,682
Recurring | Level 2
Financial Assets
Total financial assets	297,045	191,719
Recurring | Level 2 | Government agency securities
Financial Assets
Marketable securities	153,988	107,645
Recurring | Level 2 | Commercial paper
Financial Assets
Marketable securities	92,849	41,904
Recurring | Level 2 | Corporate notes/bonds
Financial Assets
Marketable securities	$ 50,208	$ 42,170

Accrued Expenses (Details)

Accrued Expenses (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Accrued Expenses
External research and development expenses	$ 6,795	$ 12,820
Employee related expenses	4,439	5,323
Intellectual property and patent related fees	2,320	4,240
Professional service expenses	660	533
Other expenses	505	359
Sublicensing expenses	413	771
Total accrued expenses	$ 15,132	$ 24,046

Property and Equipment, net (De

Property and Equipment, net (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Property and equipment disclosures
Total property and equipment	$ 26,083	$ 25,115
Less: accumulated depreciation	(11,988)	(11,095)
Property and equipment, net	14,095	14,020
Laboratory equipment
Property and equipment disclosures
Total property and equipment	18,282	18,433
Leasehold improvements
Property and equipment disclosures
Total property and equipment	5,341	4,967
Construction-in-progress
Property and equipment disclosures
Total property and equipment	1,245	500
Computer equipment
Property and equipment disclosures
Total property and equipment	858	858
Furniture and office equipment
Property and equipment disclosures
Total property and equipment	239	239
Software
Property and equipment disclosures
Total property and equipment	$ 118	$ 118

Commitments and Contingencies -

Commitments and Contingencies - Licensor Expense Reimbursement (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Licensor Expense Reimbursement
Commitments and contingencies
Expense for prosecution and maintenance of patent rights	$ 3.8	$ 3.8

Collaboration and Profit-Shar_3

Collaboration and Profit-Sharing Agreements - Allegran pharmaceuticals strategic alliance and profit sharing agreement (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Collaboration and Profit-Sharing Agreements
Revenue recognized	$ 5,706
Collaboration and other research and development revenues	6,499	$ 5,723
Deferred revenue	$ 89,371		$ 94,927

Collaboration and Profit-Shar_4

Collaboration and Profit-Sharing Agreements - Revenue Recognition (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2021USD ($)
Accounts receivable
Accounts receivable, Balance at Beginning of Period	$ 6,048
Accounts Receivable, Additions	316
Accounts Receivable, Deductions	(5,692)
Accounts receivable, Balance at End of Period	672
Contract liabilities:
Deferred Revenue, Balance at Beginning of Period	94,927
Deferred revenue, Additions	150
Deferred revenue, Deductions	(5,706)
Deferred Revenue, Balance at End of Period	$ 89,371

Collaboration and Profit-Shar_5

Collaboration and Profit-Sharing Agreements - Contract Assets and Liability (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2021USD ($)
Change in contract asset and contract liability balances
Amounts included in deferred revenue at the beginning of the period	$ 5,706

Stock-Based Compensation - Expe

Stock-Based Compensation - Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Stock-based compensation disclosures
Compensation expense	$ 12,204	$ 6,220
Research and development
Stock-based compensation disclosures
Compensation expense	3,966	3,057
General and administrative
Stock-based compensation disclosures
Compensation expense	$ 8,238	$ 3,163

Stock-Based Compensation - Rest

Stock-Based Compensation - Restricted Stock and Stock Options (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Weighted Average Grant Date Fair Value
Compensation expense	$ 12,204	$ 6,220
Restricted Stock
Changes in unvested restricted stock
Unvested restricted shares, beginning of period (in shares)	507,450
Issued (in shares)	424,017
Vested (in shares)	(79,397)
Forfeited (in shares)	(54,036)
Unvested restricted shares, end of period(in shares)	798,034		507,450
Weighted Average Grant Date Fair Value
Balance, beginning of period	$ 27.35
Issued (in dollars per share)	52.49
Vested (in dollars per share)	27.48
Forfeited (in dollars per share)	32.69
Balance, ending of period	$ 40.94		$ 27.35
Unrecognized stock-based compensation expense	$ 24,800
Period for recognition	2 years 6 months
Stock options
Weighted Average Grant Date Fair Value
Unrecognized stock-based compensation expense	$ 41,600
Period for recognition	2 years 7 months 6 days
Changes in unvested stock options
Outstanding, beginning of period (in shares)	3,912,257
Granted (in shares)	913,803
Exercised (in shares)	(501,162)
Cancelled (in shares)	(488,579)
Outstanding, end of period (in shares)	3,836,319		3,912,257
Exercisable (in shares)	1,503,421
Outstanding, beginning of period (in dollars per share)	$ 27.26
Granted (in dollars per share)	46.42
Exercised (in dollars per share)	23.95
Cancelled (in dollars per share)	28.19
Outstanding, end of period (in dollars per share)	32.14		$ 27.26
Exercisable (in dollar per share)	$ 25.21
Remaining contractual life	7 years 1 month 6 days		7 years 10 months 24 days
Exercisable, remaining contractual life	4 years 3 months 18 days
Aggregate intrinsic value	$ 43,349		$ 167,640
Exercisable, aggregated intrinsic value	$ 25,238

Net Income (Loss) per Share - A

Net Income (Loss) per Share - Anti-dilutive (Details) - shares	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Potentially dilutive securities
Anti-dilutive common stock equivalent shares	4,634,353	5,501,001
Restricted Stock
Potentially dilutive securities
Anti-dilutive common stock equivalent shares	798,034	638,054
Stock options
Potentially dilutive securities
Anti-dilutive common stock equivalent shares	3,836,319	4,862,947

Uncategorized Items - edit-2021

Label	Element	Value
Fair Value Measurements Recurring [Member] | Money Market Funds [Member]
Restricted Cash and Cash Equivalents	us-gaap_RestrictedCashAndCashEquivalents	$ 3,877,000
Restricted Cash and Cash Equivalents	us-gaap_RestrictedCashAndCashEquivalents	3,877,000
Fair Value Inputs Level1 [Member] | Fair Value Measurements Recurring [Member] | Money Market Funds [Member]
Restricted Cash and Cash Equivalents	us-gaap_RestrictedCashAndCashEquivalents	3,877,000
Restricted Cash and Cash Equivalents	us-gaap_RestrictedCashAndCashEquivalents	$ 3,877,000