CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Cash flows from operating activities:
Net (loss) income	$ (17,455)	$ (12,746)
Adjustments to reconcile net (loss) income to net cash provided by (used in) operating activities:
Depreciation and amortization	10,899	11,531
(Recovery) provision for doubtful accounts	(43)	(214)
Stock-based compensation expense	2,255	3,393
Non-cash provision for restructuring	934	2,477
Non-cash interest expense	6,149	5,214
Unrealized foreign currency transaction losses	(921)	4,763
Benefit for deferred taxes	5	(746)
Changes in operating assets and liabilities, net of effects from acquisitions:
Accounts receivable	13,525	9,343
Inventories	653	9,482
Prepaid expenses and other current assets	2,454	(3,287)
Accounts payable	3,426	980
Accrued expenses, compensation and benefits and other liabilities	(12,275)	(3,419)
Income taxes payable	(37)	991
Deferred revenues	(10,070)	(21,690)
Net cash provided by (used in) operating activities	(501)	6,072
Cash flows from investing activities:
Purchases of property and equipment	(4,888)	(3,108)
Increase in other long-term assets	(17)	(23)
Net cash used in investing activities	(4,905)	(3,131)
Cash flows from financing activities:
Proceeds from long-term debt	22,688	0
Repayment of debt	(4,723)	(2,500)
Proceeds from the issuance of common stock under employee stock plans	256	217
Common stock repurchases for tax withholdings for net settlement of equity awards	(649)	(497)
Net cash (used in) provided by financing activities	17,572	(2,780)
Effect of exchange rate changes on cash and cash equivalents	(399)	625
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect	11,767	786
Cash and cash equivalents at beginning of period	57,223
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	72,200	50,734
Supplemental Cash Flow Information [Abstract]
Cash and cash equivalents at end of period	60,209	47,434
Restricted Cash, Current	8,500	0
Restricted Cash, Noncurrent	3,491	3,300
Cash paid for income taxes, net of refunds	(2,051)	261
Cash paid for interest	$ 5,829	$ 4,450