CONSOLIDATED STATEMENTS OF STOCKHOLDERS' DEFICIT - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Series A Convertible Preferred Stock	Additional paid-in capital	Shareholder note receivable	Treasury stock	Accumulated other comprehensive income (loss)	Accumulated deficit
Balance beginning, value at Dec. 31, 2015	$ (36,576)	$ 1		$ 416,948	$ (5,000)	$ (97)	$ (21,188)	$ (427,240)
Balance beginning, shares at Dec. 31, 2015		8,513
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	1,626			1,626
Repurchase and/or forfeiture of common stock, shares		(1)
Shares issued for consulting services	25			25
Shares issued for consulting services, shares		210
Issuance of common stock for employee stock purchase plan	114			114
Issuance of common stock for employee stock purchase plan, shares		58
Warrant conversion	1,074			1,074
Warrant conversion, shares		269
Foreign currency translation adjustments	22,158						22,158
Net loss	(29,925)							(29,925)
Balance ending, value at Dec. 31, 2016	(41,504)	$ 1		419,787	(5,000)	(97)	970	(457,165)
Balance ending, shares at Dec. 31, 2016		9,049
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	3,902			3,902
Common and preferred stock and warrants issued in private placement, net of offering costs of $1.7 million	17,118	$ 1		17,117
Shares issued for acquisition of intangible assets	473			473
Shares issued for acquisition of intangible assets, shares		285
Common and preferred stock and warrants issued in private placement, net of offering costs, shares		1,810	15
Conversion of preferred stock into common stock, shares		4,964	(10)
Issuance of common stock for employee stock purchase plan	231			231
Issuance of common stock for employee stock purchase plan, shares		128
Common stock issued for vesting of restricted stock awards, net of shares repurchased for tax liability, shares		183
Common stock issued for warrant exercises	3,337			3,337
Common stock issued for warrant exercises, shares		1,668
Warrant derivative liability reclassified to equity due to exercise of warrants	2,311			2,311
Issuance of common stock and warrants to board members	4,000			4,000
Issuance of common stock and warrants to board members, shares		1,770
Net change from reclassification of warrants to and from liability	(14,355)			(14,355)
Foreign currency translation adjustments	123						123
Net loss	(2,294)							(2,294)
Balance ending, value at Dec. 31, 2017	$ (26,658)	$ 2		$ 436,803	$ (5,000)	$ (97)	$ 1,093	$ (459,459)
Balance ending, shares at Dec. 31, 2017		19,857	5