Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Deficit	Treasury Stock	Accumulated Other Comprehensive Income (Loss)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock, par value (usd per share)		$ 10,000
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		$ 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		643,150	(621,743)	(4,027)	1,990
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		640,789	(599,715)	(4,026)	2,588
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(49,162)
Balance at end of period (in shares) at Jun. 30, 2019		17,409,000
Balance at end of period at Jun. 30, 2019	72,076		722,478	(648,877)	(4,120)	2,578
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock, par value (usd per share)		$ 10,000
Balance at beginning of period (in shares) at Mar. 31, 2019		10,391,000
Balance at beginning of period at Mar. 31, 2019	19,380		643,150	(621,743)	(4,027)	1,990
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Treasury shares purchased (in shares)		13,000
Treasury shares purchased	(93)				(93)
Deerfield warrants	4,854		4,854
Employee stock purchase plan (in shares)		42,000
Employee stock purchase plan	207		207
Equity conversion option	18,651		18,651
Stock-based compensation expense	1,355		1,355
Issuance of restricted stock (in shares)		35,000
Prepaid warrants	9,700		9,700
Restricted stock expense	1,168		1,168
Issuance of common stock (in shares)		6,422,000
Issuance of common stock	42,285		42,279
Shares issued upon conversion of debt (in shares)		506,000
Shares issued upon conversion of debt	1,877		1,876
Debt issuance costs allocated to equity	(762)		(762)
Net loss	(27,134)			(27,134)
Other comprehensive income	588					588
Balance at end of period (in shares) at Jun. 30, 2019		17,409,000
Balance at end of period at Jun. 30, 2019	$ 72,076		722,478	(648,877)	(4,120)	2,578
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock, par value (usd per share)		$ 17,000
Issuance of common stock, par value (usd per share)	$ 0.001
Preferred Stock, beginning balance (in shares) at Dec. 31, 2019	0
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		19,215,000
Balance at end of period at Mar. 31, 2020	$ 53,323	$ 19	737,599	(682,588)	(4,271)	2,564
Preferred Stock, beginning balance (in shares) at Dec. 31, 2019	0
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]
Net loss	$ (44,208)
Preferred Stock, ending balance (in shares) at Jun. 30, 2020	15,000
Balance at end of period (in shares) at Jun. 30, 2020	19,173,845	19,299,000
Balance at end of period at Jun. 30, 2020	$ 28,417	$ 19	738,571	(708,681)	(4,278)	2,786
Preferred Stock, beginning balance (in shares) at Mar. 31, 2020	15,000
Balance at beginning of period (in shares) at Mar. 31, 2020		19,215,000
Balance at beginning of period at Mar. 31, 2020	$ 53,323	$ 19	737,599	(682,588)	(4,271)	2,564
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Treasury shares purchased (in shares)		8,000
Treasury shares purchased	(7)				(7)
Employee stock purchase plan	50
Stock-based compensation expense	723		723
Issuance of restricted stock (in shares)		76,000
Restricted stock expense	199		199
Net loss	(26,093)			(26,093)
Other comprehensive income	$ 222					222
Preferred Stock, ending balance (in shares) at Jun. 30, 2020	15,000
Balance at end of period (in shares) at Jun. 30, 2020	19,173,845	19,299,000
Balance at end of period at Jun. 30, 2020	$ 28,417	$ 19	$ 738,571	$ (708,681)	$ (4,278)	$ 2,786
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock, par value (usd per share)	$ 0.001	$ 6,000
Shares issued upon conversion of debt, par value (usd per share)		$ 1,000