CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Cash flows from operating activities:
Net income	$ 3,448	$ 3,068
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	3,960	1,582
Non-cash interest expense	1,036	970
Stock-based compensation expense	2,268	1,531
Deferred tax expense	449	10
Loss on conversion of senior convertible notes	1
Loss on disposal of assets		59
Changes in assets and liabilities:
Accounts receivable	(1,529)	(2,415)
Other receivables	127	172
Inventories	(1,188)	851
Prepaid expenses and other current assets	(1,608)	34
Accounts payable	(1,550)	(452)
Accrued liabilities	(3,839)	(4,220)
Long-term liabilities	(3)	(43)
Net cash provided by operating activities	1,572	1,147
Cash flows from investing activities:
Purchases of marketable securities		(28)
Redemptions of marketable securities		7,400
Purchases of property, plant and equipment	(1,564)	(1,295)
Net cash (used in) provided by investing activities	(1,564)	6,077
Cash flows from financing activities:
Exercise of stock options	344	1,333
Repayment of senior convertible notes	(11)
Payment of contingent consideration		(1,663)
Net cash provided by (used in) financing activities	333	(330)
Effect of exchange rate changes on cash and cash equivalents	(224)	536
Net increase (decrease) in cash and cash equivalents	117	7,430
Cash, cash equivalents and restricted cash, beginning of period	173,759	122,683
Cash, cash equivalents and restricted cash, end of period	173,876	130,113
Supplemental disclosure of non-cash activities:
Income taxes paid	937	1,181
Non-cash effect of adoption of ASU 2016-16	$ 5,609
Payment of contingent consideration in common stock		$ 1,062