Consolidated Statements of Shareholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock [Member]	Treasury Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive Loss [Member]
Balance at Dec. 31, 2014	$ 121,789	$ 63		$ 257,642	$ (135,916)
Balance, Shares at Dec. 31, 2014		63,183
Stock-based compensation	3,311			3,311
Issuance of common stock, net of issuance costs	58,331	$ 21		58,310
Issuance of common stock, net of issuance costs, Shares		20,756
Issuance of common stock, acquisition	43,677	$ 15		43,662
Issuance of common stock, acquisition, Shares		15,543
Exercise of stock options and restricted stock units	259	$ 1		258
Exercise of stock options and restricted stock units, Shares		698
Return of common stock to pay withholding taxes on restricted stock	(73)		$ (73)
Return of common stock to pay withholding taxes on restricted stock, Shares			(31)
Issuance of warrants and relative fair value of warrants issued with debt	97			97
Other comprehensive loss	(3,166)					$ (3,166)
Net loss	(46,948)				(46,948)
Balance at Dec. 31, 2015	177,277	$ 100	$ (73)	363,280	(182,864)	(3,166)
Balance, Shares at Dec. 31, 2015		100,180	(31)
Stock-based compensation	5,033			5,033
Issuance of common stock, net of issuance costs	58,029	$ 15		58,014
Issuance of common stock, net of issuance costs, Shares		15,086
Exercise of stock options and restricted stock units	166			166
Exercise of stock options and restricted stock units, Shares		419
Return of common stock to pay withholding taxes on restricted stock	(168)		$ (168)
Return of common stock to pay withholding taxes on restricted stock, Shares			(63)
Issuance of common stock for services	116			116
Issuance of common stock for services, Shares		96
Other comprehensive loss	(2,603)					(2,603)
Net loss	(119,980)				(119,980)
Balance at Dec. 31, 2016	117,870	$ 115	$ (241)	426,609	(302,844)	(5,769)
Balance, Shares at Dec. 31, 2016		115,781	(94)
Stock-based compensation	7,078			7,078
Non-employee warrant awards	838			838
Issuance of common stock and treasury stock, net of issuance costs	68,864	$ 45	$ 409	68,410
Issuance of common stock and treasury stock, net of issuance costs, Shares		44,689	213
Exercise of stock options and warrants	112,838	$ 35		112,803
Exercise of stock options and warrants, Shares		34,749
Award of restricted stock units		340
Return of common stock to pay withholding taxes on restricted stock	(168)		$ (168)
Return of common stock to pay withholding taxes on restricted stock, Shares			(119)
Issuance of common stock in exchange for contingent consideration	5,227	$ 4		5,223
Issuance of common stock in exchange for contingent consideration, Shares		3,723
Issuance of warrants and relative fair value of warrants issued with debt	300			300
Other comprehensive loss	10,797					10,797
Net loss	(144,796)				(144,796)
Balance at Dec. 31, 2017	$ 178,848	$ 199		$ 621,261	$ (447,640)	$ 5,028
Balance, Shares at Dec. 31, 2017		199,282