CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Cash flows from operating activities:
Net (loss) income	$ (16,577)	$ (12,674)
Adjustments to reconcile net (loss) income to net cash provided by (used in) operating activities:
Depreciation and amortization	15,905	16,932
(Recovery) provision for doubtful accounts	61	(158)
Stock-based compensation expense	4,331	5,874
Non-cash provision for restructuring	1,083	3,191
Non-cash interest expense	8,697	7,255
Unrealized foreign currency transaction losses	(794)	6,885
Benefit for deferred taxes	6	(925)
Changes in operating assets and liabilities, net of effects from acquisitions:
Accounts receivable	10,129	2,877
Inventories	294	9,542
Prepaid expenses and other current assets	3,724	(3,958)
Accounts payable	3,467	2,065
Accrued expenses, compensation and benefits and other liabilities	(12,453)	543
Income taxes payable	423	(161)
Deferred revenues	(22,544)	(31,185)
Net cash provided by (used in) operating activities	(4,248)	6,103
Cash flows from investing activities:
Purchases of property and equipment	(7,540)	(6,125)
Increase in other long-term assets	(25)	(24)
Net cash used in investing activities	(7,565)	(6,149)
Cash flows from financing activities:
Proceeds from long-term debt	22,688	912
Repayment of debt	(7,808)	(3,750)
Proceeds from the issuance of common stock under employee stock plans	266	219
Common stock repurchases for tax withholdings for net settlement of equity awards	(957)	(732)
Net cash (used in) provided by financing activities	14,189	(3,351)
Effect of exchange rate changes on cash and cash equivalents	(358)	753
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect	2,018	(2,644)
Cash and cash equivalents at beginning of period	57,223
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	62,451	47,304
Supplemental Cash Flow Information [Abstract]
Cash and cash equivalents at end of period	50,460	44,094
Restricted Cash, Current	8,500	0
Restricted Cash, Noncurrent	3,491	3,210
Cash paid for income taxes, net of refunds	(2,268)	463
Cash paid for interest	$ 9,024	$ 7,406