CONDENSED CONSOLIDATED STATEMENTS OF CONVERTIBLE PREFERRED STOCK AND CHANGES IN STOCKHOLDERS' EQUITY (DEFICIT) (UNAUDITED) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income	Accumulated Deficit	Series B Preferred Stock	Series A Preferred Stock
Balance at Dec. 31, 2019	$ (51,503)		$ 3,748	$ 68	$ (55,319)
Temporary equity, Balance, Shares at Dec. 31, 2019						14,877,697	44,520,653
Temporary equity, Balance at Dec. 31, 2019						$ 120,923	$ 52,204
Balance, Shares at Dec. 31, 2019		2,099,740
Stock-based compensation	646		646
Issuance of common stock, upon vesting of restricted stock, Shares		292,644
Unrealized gain on available-for-sale securities	176			176
Net loss	(9,339)				(9,339)
Balance at Mar. 31, 2020	(60,020)		4,394	244	(64,658)
Temporary equity, Balance, Shares at Mar. 31, 2020						14,877,697	44,520,653
Temporary equity, Balance at Mar. 31, 2020						$ 120,923	$ 52,204
Balance, Shares at Mar. 31, 2020		2,392,384
Balance at Dec. 31, 2020	353,064	$ 7	478,272	(112)	(125,103)
Balance, Shares at Dec. 31, 2020		61,931,255
Stock-based compensation	8,103		8,103
Issuance of common stock, upon vesting of restricted stock, Shares		519,839
Unrealized gain on available-for-sale securities	42			42
Foreign currency translation adjustment	83			83
Net loss	(30,923)				(30,923)
Balance at Mar. 31, 2021	$ 330,369	$ 7	$ 486,375	$ 13	$ (156,026)
Balance, Shares at Mar. 31, 2021		62,451,094