Condensed Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Convertible Preferred Stock	Common Stock [Member]	Additional Paid-In Capital [Member]	Other Comprehensive Gain/(Loss) [Member]	Accumulated Deficit [Member]	Noncontrolling Interest [Member]
Beginning balance at Dec. 31, 2019	$ 21,026	$ 2	$ 4	$ 343,524	$ (40)	$ (322,304)	$ (160)
Begining balance, Shares at Dec. 31, 2019		1,643,961	3,891,787
Conversion of preferred stock to common stock		$ (2)	$ 1	1
Conversion of preferred stock to common stock, shares		(1,643,961)	587,444
Issuance of common stock upon release of restricted stock units			2,679
Issuance of common stock from underwritten follow-on offering, net of offering costs	18,779		$ 4	18,775
Issuance of common stock from underwritten follow-on offering, net of offering costs, shares			4,870,588
Stock-based compensation	423			423
Change in unrealized loss on available-for-sale investments, net of tax	(13)				(13)
Consolidated net income (loss)	1,752					1,753	(1)
Ending balance at Mar. 31, 2020	41,967		$ 9	362,723	(53)	(320,551)	(161)
Ending balance, Shares at Mar. 31, 2020			9,352,498
Beginning balance at Dec. 31, 2020	31,484		$ 11	370,210	(43)	(338,528)	(166)
Begining balance, Shares at Dec. 31, 2020			11,018,954
Issuance of common stock upon release of restricted stock units			4,177
Issuance of common stock from at the market offerings, net of offering costs	9,621		$ 2	9,619
Issuance of common stock from at the market offerings, net of offering costs, Shares			1,988,254
Issuance of common stock from committed purchase agreement, net of offering costs	15,236		$ 3	15,233
Issuance of common stock from committed purchase agreement, net of offering costs, shares			3,000,000
Stock-based compensation	360			360
Change in unrealized loss on available-for-sale investments, net of tax	(14)				(14)
Consolidated net income (loss)	(7,155)					(7,151)	(4)
Ending balance at Mar. 31, 2021	$ 49,532		$ 16	$ 395,422	$ (57)	$ (345,679)	$ (170)
Ending balance, Shares at Mar. 31, 2021			16,011,385