Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Preferred Stock	Accumulated Deficit	Treasury Stock
Balance at beginning of period (in shares) at Dec. 31, 2018		10,388,000
Balance at beginning of period at Dec. 31, 2018	$ 39,646	$ 10	$ 640,789	$ (599,715)	$ (4,026)	$ 2,588
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Treasury shares purchased	(1)
Stock-based compensation expense	1,512		1,512
Issuance of restricted stock (in shares)		3,000
Issuance of restricted stock	0
Restricted stock expense	849		849
Net loss	(22,028)			(22,028)
Other comprehensive income	(598)					(598)
Balance at end of period (in shares) at Mar. 31, 2019		10,391,000
Balance at end of period at Mar. 31, 2019	$ 19,380	$ 10	643,150	(621,743)	(4,027)	1,990
Balance at beginning of period (in shares) at Dec. 31, 2019	18,098,464	18,190,000
Balance at beginning of period at Dec. 31, 2019	$ 63,856	$ 18	730,729	(664,472)	(4,235)	1,816
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Treasury shares purchased (in shares)		26,000
Treasury shares purchased	(36)				(36)
Deerfield warrants	(375)		(375)
Equity conversion option	3,566		3,566
Stock-based compensation expense	969		969
Issuance of restricted stock (in shares)		49,000
Issuance of restricted stock	0
Restricted stock expense	764		764
Issuance of common stock (in shares)		950,000
Issuance of common stock	$ 787	$ 1	786
Issuance of Series DF-1 Preferred Stock (in shares)	15,000
Issuance of Series DF-1 Preferred Stock	$ 1,213		1,213
Debt issuance costs allocated to equity	(53)		(53)
Net loss	(18,116)			(18,116)
Other comprehensive income	$ 748					748
Preferred Stock, ending balance (in shares) at Mar. 31, 2020	15,000
Balance at end of period (in shares) at Mar. 31, 2020	19,097,506	19,215,000
Balance at end of period at Mar. 31, 2020	$ 53,323	$ 19	$ 737,599	$ (682,588)	$ (4,271)	$ 2,564