RESTATEMENT OF PREVIOUSLY REPORTED UNAUDITED CONDENSED CONSOLIDATED FINANCIAL STATEMENTS - Effects of Restatement on Unaudited Condensed Consolidated Statements of Cash Flows (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Cash flows from operating activities:
Net loss	$ (5,268)	$ (17,841)	$ (1,546)	$ (18,232)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization			6,814	4,868
Reserve for potential tax credits monetization			0	1,700
Reserve for doubtful accounts			919	135
Equity-based compensation cost			2,399	2,641
Gain on disposal of property and equipment			(661)	(185)
Amortization of loan issuance costs and debt discounts			1,865	1,901
Gain on debt extinguishment			0	(53)
Unrealized (gain) loss on foreign currency transactions			(607)	2,131
Deferred taxes			2,023	62
Changes in operating assets and liabilities			(1,506)	(5,531)
Net cash provided by (used in) operating activities			10,794	(10,563)
Cash flows from investing activities:
Purchase of property and equipment			(598)	(703)
Proceeds from sale of property and equipment			674	193
Net cash provided by (used in) investing activities			76	(510)
Cash flows from financing activities:
Long-term debt and finance lease repayments			(428)	(995)
Long-term debt borrowings			9,666	15,000
Stock issuance costs			0	(1,712)
Purchase of treasury stock			(366)	(175)
Net cash provided by financing activities			7,472	12,118
Effect of exchange rate changes on cash, cash equivalents and restricted cash			2	(183)
Net change in cash, cash equivalents and restricted cash			18,344	862
Cash, cash equivalents and restricted cash at the beginning of year			7,850	3,734
Cash, cash equivalents and restricted cash at the end of period	$ 26,194	4,596	$ 26,194	4,596
Previously Reported
Cash flows from operating activities:
Net loss		(33,346)		(34,820)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization				4,868
Reserve for doubtful accounts				19,120
Equity-based compensation cost				2,641
Gain on disposal of property and equipment				(185)
Amortization of loan issuance costs and debt discounts				1,901
Gain on debt extinguishment				(53)
Unrealized (gain) loss on foreign currency transactions				2,131
Changes in operating assets and liabilities				(5,674)
Net cash provided by (used in) operating activities				(10,071)
Cash flows from investing activities:
Purchase of property and equipment				(703)
Proceeds from sale of property and equipment				193
Net cash provided by (used in) investing activities				(510)
Cash flows from financing activities:
Long-term debt and finance lease repayments				(995)
Long-term debt borrowings				15,000
Stock issuance costs				(2,179)
Purchase of treasury stock				(175)
Net cash provided by financing activities				11,651
Effect of exchange rate changes on cash, cash equivalents and restricted cash				(183)
Net change in cash, cash equivalents and restricted cash				887
Cash, cash equivalents and restricted cash at the beginning of year				3,654
Cash, cash equivalents and restricted cash at the end of period		4,541		4,541
Adjustments
Cash flows from operating activities:
Net loss		15,505		16,588
Adjustments to reconcile net loss to net cash used in operating activities:
Reserve for potential tax credits monetization				1,700
Reserve for doubtful accounts				(18,985)
Deferred taxes				62
Changes in operating assets and liabilities				143
Net cash provided by (used in) operating activities				(492)
Cash flows from financing activities:
Stock issuance costs				467
Net cash provided by financing activities				467
Net change in cash, cash equivalents and restricted cash				(25)
Cash, cash equivalents and restricted cash at the beginning of year				80
Cash, cash equivalents and restricted cash at the end of period		$ 55		$ 55