UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock	AOCI Attributable to Parent	Accumulated Deficit
Balance, beginning of period at Dec. 31, 2017		$ 321,024	$ (5,189)	$ (299,108)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Warrant exercises		5,533
Share-based compensation		5,757
Shares issued in equity financing		5,467
Services settled by issuance of shares		0
Shares issued to senior secured lender		323
Conversion of notes	$ 1,992	1,314
Foreign currency translation loss, net of tax			(207)
Net loss	(12,472)			(12,472)
Balance, end of period at Sep. 30, 2018	22,442	339,418	(5,396)	(311,580)
Balance, beginning of period at Dec. 31, 2017		321,024	(5,189)	(299,108)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(18,024)
Balance, end of period at Dec. 31, 2018	130,133	453,995	(6,716)	(317,146)
Balance, beginning of period at Jun. 30, 2018		331,512	(5,359)	(302,029)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Warrant exercises		2,463
Share-based compensation		4,238
Services settled by issuance of shares		0
Shares issued to senior secured lender		205
Conversion of notes		1,000
Foreign currency translation loss, net of tax			(37)
Net loss	(9,551)			(9,551)
Balance, end of period at Sep. 30, 2018	22,442	339,418	(5,396)	(311,580)
Balance, beginning of period at Dec. 31, 2018	130,133	453,995	(6,716)	(317,146)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Warrant exercises		2,188
Warrants issued		6,781
Share-based compensation		10,416
Shares issued in equity financing		30,899
Services settled by issuance of shares		7,529
Shares issued for acquisitions		30,302
Stock option exercises		211
Shares issued to senior secured lender		3,775
Conversion of notes	147	147
Foreign currency translation loss, net of tax			(6,805)
Net loss	(55,743)			(55,743)
Balance, end of period at Sep. 30, 2019	159,833	546,243	(13,521)	(372,889)
Balance, beginning of period at Jun. 30, 2019		499,020	(8,034)	(347,770)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Warrants issued		6,781
Share-based compensation		2,672
Shares issued in equity financing		30,899
Services settled by issuance of shares		4,702
Stock option exercises		1
Shares issued to senior secured lender		2,168
Foreign currency translation loss, net of tax			(5,487)
Net loss	(25,119)			(25,119)
Balance, end of period at Sep. 30, 2019	$ 159,833	$ 546,243	$ (13,521)	$ (372,889)