Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Asset Purchase Agreement	Follow-on Public Offering	November 2019	July 13, 2020	August 10, 2020	Common Stock	Common Stock Asset Purchase Agreement	Common Stock Follow-on Public Offering	Common Stock March 20, 2019	Common Stock June 12, 2019	Common Stock March 12, 2020	Common Stock May 17, 2019	Common Stock June 30, 2020	Common Stock December 17, 2020	Common Stock August 2019	Common Stock November 2019	Common Stock July 13, 2020	Common Stock July 20, 2020	Common Stock September 30, 2020	Common Stock August 10, 2020	Common Stock December 14, 2020	Additional Paid-in Capital	Additional Paid-in Capital Asset Purchase Agreement	Additional Paid-in Capital Follow-on Public Offering	Additional Paid-in Capital November 2019	Additional Paid-in Capital July 13, 2020	Additional Paid-in Capital August 10, 2020	Accumulated Deficit	Accumulated Other Comprehensive Income
Beginning balance at Dec. 31, 2018	$ 5,369						$ 1																$ 76,348						$ (71,020)	$ 40
Beginning balance, shares at Dec. 31, 2018							11,534,190
Net loss	(58,789)																												(58,789)
Issuance of restricted common stock, shares										2,406,618	64,982		19,407			84,975	25,990
Issuance of common stock	29,447						$ 1																29,446
Issuance of common stock, shares							3,600,000
Stock-based compensation	34,681																						34,681
Exercise of stock options	2																						2
Exercise of stock options, shares							487
Other comprehensive income (loss)	17																													17
Ending balance at Dec. 31, 2019	10,727						$ 2																140,477						(129,809)	57
Ending balance, shares at Dec. 31, 2019							17,736,649
Net loss	(63,126)																												(63,126)
Issuance of restricted common stock				$ 659	$ 49	$ 760																				$ 659	$ 49	$ 760
Issuance of restricted common stock, shares												439,145		134,364	23,500		90,000	10,000	95,500	22,700	90,000	890,000
Issuance of common stock		$ 29,077	$ 23,416					$ 1																$ 29,076	$ 23,416
Issuance of common stock, shares								4,220,000	3,860,710
Forfeiture of restricted common stock, shares												371,329		(134,366)
Issuance of 25,000 warrants on August 18, 2020	204																						204
Stock-based compensation	21,770																						21,770
Exercise of stock options	$ 44																						44
Exercise of stock options, shares	10,697						10,697
Other comprehensive income (loss)	$ (48)																													(48)
Ending balance at Dec. 31, 2020	23,382						$ 3																216,305						$ (192,935)	$ 9
Ending balance, shares at Dec. 31, 2020							27,074,791
Shares of common stock retired in connection with vesting	$ (150)																						$ (150)
Shares of restricted common stock retired in connection with vesting, shares							42,779