Condensed Consolidated Statements Of Stockholders' Equity/(Deficit) - USD ($) shares in Thousands, $ in Thousands	Total	Series B	Series F	Preferred Stock Series B	Preferred Stock Series F	Common Stock	Additional paid-in capital	Additional paid-in capital Series F	Other Comprehensive Loss	Accumulated deficit	Accumulated deficit Series B
Balances, shares, beginning balance at Dec. 31, 2017				44	0	32,560
Balances, beginning balance at Dec. 31, 2017	$ 271,321			$ 0	$ 0	$ 326	$ 572,342		$ (315)	$ (301,032)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Declared and paid dividends on preferred stock		$ (32)									$ (32)
Common stock forfeited for tax payment, shares						(27)
Common stock forfeited for tax payment	(1,455)						(1,455)
Common stock issued from exercise of rights offering, shares						200
Common stock issued from exercise of rights offering	4,720					$ 2	4,718
Options exercised, shares						3
Options exercised	50						50
Stock-based compensation	547						547
Comprehensive income	115								115
Net loss	(26,233)									(26,233)
Balances, shares, endings balance at Mar. 31, 2018				44	0	32,736
Balances, ending balance at Mar. 31, 2018	248,979			$ 0	$ 0	$ 328	576,202		(200)	(327,351)
Balances, shares, beginning balance at Dec. 31, 2017				44	0	32,560
Balances, beginning balance at Dec. 31, 2017	271,321			$ 0	$ 0	$ 326	572,342		(315)	(301,032)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(97,122)
Balances, shares, endings balance at Sep. 30, 2018				44	0	32,736
Balances, ending balance at Sep. 30, 2018	179,672			$ 0	$ 0	$ 328	577,737		(89)	(398,304)
Balances, shares, beginning balance at Mar. 31, 2018				44	0	32,736
Balances, beginning balance at Mar. 31, 2018	248,979			$ 0	$ 0	$ 328	576,202		(200)	(327,351)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Declared and paid dividends on preferred stock		(32)									(32)
Stock-based compensation	570						570
Comprehensive income	72								72
Net loss	(36,997)									(36,997)
Balances, shares, endings balance at Jun. 30, 2018				44	0	32,736
Balances, ending balance at Jun. 30, 2018	212,592			$ 0	$ 0	$ 328	576,772		(128)	(364,380)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Declared and paid dividends on preferred stock		(32)									(32)
Common stock forfeited for tax payment	489						489
Stock-based compensation	476						476
Comprehensive income	39								39
Net loss	(33,892)									(33,892)
Balances, shares, endings balance at Sep. 30, 2018				44	0	32,736
Balances, ending balance at Sep. 30, 2018	179,672			$ 0	$ 0	$ 328	577,737		(89)	(398,304)
Balances, shares, beginning balance at Dec. 31, 2018				44	0	34,403
Balances, beginning balance at Dec. 31, 2018	211,839			$ 0	$ 1	$ 344	651,623		(219)	(439,910)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Declared and paid dividends on preferred stock		(32)									(32)
Common stock forfeited for tax payment, shares						(10)
Common stock forfeited for tax payment	(106)						(106)
Stock issuance, shares						20
Stock issuance	0		$ 14,340					$ 14,340
Stock-based compensation	1,808						1,808
Comprehensive income	35								35
Net loss	(37,575)									(37,575)
Balances, shares, endings balance at Mar. 31, 2019				44	0	34,413
Balances, ending balance at Mar. 31, 2019	190,309			$ 0	$ 1	$ 344	667,665		(184)	(477,517)
Balances, shares, beginning balance at Dec. 31, 2018				44	0	34,403
Balances, beginning balance at Dec. 31, 2018	211,839			$ 0	$ 1	$ 344	651,623		(219)	(439,910)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(100,064)
Balances, shares, endings balance at Sep. 30, 2019				44	0	34,454
Balances, ending balance at Sep. 30, 2019	181,531			$ 0	$ 1	$ 344	721,354		(99)	(540,069)
Balances, shares, beginning balance at Mar. 31, 2019				44	0	34,413
Balances, beginning balance at Mar. 31, 2019	190,309			$ 0	$ 1	$ 344	667,665		(184)	(477,517)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Declared and paid dividends on preferred stock		(32)									(32)
Stock issuance, shares						5
Stock issuance	(5)		30,115				(5)	30,115
Stock-based compensation	894						894
Comprehensive income	123								123
Net loss	(36,090)									(36,090)
Balances, shares, endings balance at Jun. 30, 2019				44	0	34,418
Balances, ending balance at Jun. 30, 2019	185,314			$ 0	$ 1	$ 344	698,669		(61)	(513,639)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Declared and paid dividends on preferred stock		$ (32)									$ (32)
Stock issuance, shares						36
Stock issuance	0		$ 21,932				0	$ 21,932
Stock-based compensation	753						753
Comprehensive income	(38)								(38)
Net loss	(26,399)									(26,399)
Balances, shares, endings balance at Sep. 30, 2019				44	0	34,454
Balances, ending balance at Sep. 30, 2019	$ 181,531			$ 0	$ 1	$ 344	$ 721,354		$ (99)	$ (540,069)