CONDENSED CONSOLIDATED STATEMENTS OF CONVERTIBLE PREFERRED STOCK AND CHANGES IN STOCKHOLDERS' 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, 2018	$ (30,622)		$ 858		$ (31,480)
Temporary equity, Balance, Shares at Dec. 31, 2018							42,066,666
Temporary equity, Balance at Dec. 31, 2018							$ 52,204
Balance, Shares at Dec. 31, 2018		747,231
Issuance of common stock, upon vesting of restricted stock, Shares		140,106
Stock-based compensation	231		231
Net loss	(2,524)				(2,524)
Balance at Mar. 31, 2019	(32,915)		1,089		(34,004)
Temporary equity, Balance, Shares at Mar. 31, 2019							42,066,666
Temporary equity, Balance at Mar. 31, 2019							$ 52,204
Balance, Shares at Mar. 31, 2019		887,337
Balance at Dec. 31, 2018	(30,622)		858		(31,480)
Temporary equity, Balance, Shares at Dec. 31, 2018							42,066,666
Temporary equity, Balance at Dec. 31, 2018							$ 52,204
Balance, Shares at Dec. 31, 2018		747,231
Unrealized (loss) gain on available-for-sale securities	129
Net loss	(7,826)
Balance at Jun. 30, 2019	(36,647)		2,530	$ 129	(39,306)
Temporary equity, Balance, Shares at Jun. 30, 2019						14,877,697	42,066,666
Temporary equity, Balance at Jun. 30, 2019						$ 120,923	$ 52,204
Balance, Shares at Jun. 30, 2019		1,398,213
Balance at Mar. 31, 2019	(32,915)		1,089		(34,004)
Temporary equity, Balance, Shares at Mar. 31, 2019							42,066,666
Temporary equity, Balance at Mar. 31, 2019							$ 52,204
Balance, Shares at Mar. 31, 2019		887,337
Issuance of Series B Preferred Stock, net of $330 issuance costs						$ 120,923
Issuance of Series B Preferred Stock, net of $330 issuance costs, Shares						14,877,697
Issuance of common stock, upon vesting of restricted stock, Shares		510,876
Unrealized (loss) gain on available-for-sale securities	129			129
Stock-based compensation	1,441		1,441
Net loss	(5,302)				(5,302)
Balance at Jun. 30, 2019	(36,647)		2,530	129	(39,306)
Temporary equity, Balance, Shares at Jun. 30, 2019						14,877,697	42,066,666
Temporary equity, Balance at Jun. 30, 2019						$ 120,923	$ 52,204
Balance, Shares at Jun. 30, 2019		1,398,213
Balance at Dec. 31, 2019	$ (51,503)		3,748	68	(55,319)
Temporary equity, Balance, Shares at Dec. 31, 2019	59,398,350					14,877,697	44,520,653
Temporary equity, Balance at Dec. 31, 2019	$ 173,127					$ 120,923	$ 52,204
Balance, Shares at Dec. 31, 2019		2,099,740
Issuance of common stock, upon vesting of restricted stock, Shares		292,644
Unrealized (loss) gain on available-for-sale securities	176			176
Stock-based compensation	646		646
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, 2019	$ (51,503)		3,748	68	(55,319)
Temporary equity, Balance, Shares at Dec. 31, 2019	59,398,350					14,877,697	44,520,653
Temporary equity, Balance at Dec. 31, 2019	$ 173,127					$ 120,923	$ 52,204
Balance, Shares at Dec. 31, 2019		2,099,740
Unrealized (loss) gain on available-for-sale securities	42
Net loss	(20,971)
Balance at Jun. 30, 2020	$ (71,294)		4,886	110	(76,290)
Temporary equity, Balance, Shares at Jun. 30, 2020	59,398,350					14,877,697	44,520,653
Temporary equity, Balance at Jun. 30, 2020	$ 173,127					$ 120,923	$ 52,204
Balance, Shares at Jun. 30, 2020		2,801,859
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
Issuance of common stock, upon vesting of restricted stock, Shares		409,475
Unrealized (loss) gain on available-for-sale securities	(134)			(134)
Stock-based compensation	492		492
Net loss	(11,632)				(11,632)
Balance at Jun. 30, 2020	$ (71,294)		$ 4,886	$ 110	$ (76,290)
Temporary equity, Balance, Shares at Jun. 30, 2020	59,398,350					14,877,697	44,520,653
Temporary equity, Balance at Jun. 30, 2020	$ 173,127					$ 120,923	$ 52,204
Balance, Shares at Jun. 30, 2020		2,801,859