CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Preferred Stock	Common Stock	Treasury Stock	Accumulated Other Comprehensive Loss	Accumulated Deficit
Beginning balance (in shares) at Dec. 31, 2013		12	4,723	0
Beginning balance at Dec. 31, 2013	$ 3,894	$ 38,389	$ 253,270	$ 0	$ 0	$ (287,765)
Increase (Decrease) in Shareholders' Equity
Net loss	(19,920)					(19,920)
Compensation expense related to stock options granted	839		$ 839
Exercise of stock purchase warrants (in shares)			408
Exercise of stock purchase warrants	2,490		$ 2,490
Issuance of common stock, net of issuance costs (in shares)			18,655
Issuance of common stock, net of issuance costs	48,409		$ 48,409
Foreign currency translation adjustment	(71)				(71)
Ending balance (in shares) at Dec. 31, 2014		12	23,786	0
Ending balance at Dec. 31, 2014	35,641	$ 38,389	$ 305,008	$ 0	(71)	(307,685)
Increase (Decrease) in Shareholders' Equity
Net loss	(16,340)					(16,340)
Preferred stock exchanged for common stock (in shares)		1		(1,250)
Conversion of Series A preferred stock for common stock	0	$ 3,150		$ (3,150)
Compensation expense related to stock options granted	2,747		$ 2,747
Exercised (in shares)			3
Stock option exercises	11		$ 11
Foreign currency translation adjustment	71				71
Ending balance (in shares) at Dec. 31, 2015		13	23,789	(1,250)
Ending balance at Dec. 31, 2015	22,130	$ 41,539	$ 307,766	$ (3,150)	0	(324,025)
Increase (Decrease) in Shareholders' Equity
Net loss	(19,566)					(19,566)
Conversion of Series A preferred stock for common stock (in shares)		(1)		1,250
Conversion of Series A preferred stock for common stock	0	$ (3,150)		$ 3,150
Compensation expense related to stock options granted	2,499		$ 2,499
Issuance of common stock, net of issuance costs (in shares)			7,538
Issuance of common stock, net of issuance costs	18,868		$ 18,868
Exercised (in shares)			39
Stock option exercises	120		$ 120
Shares purchased during period (in shares)			229
Shares issued under the Employee Stock Purchase Plan	467		$ 467
Foreign currency translation adjustment	0
Issuance of warrants	190		$ 190
Ending balance (in shares) at Dec. 31, 2016		12	31,595	0
Ending balance at Dec. 31, 2016	$ 24,708	$ 38,389	$ 329,910	$ 0	$ 0	$ (343,591)