CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Operating activities
Net income (loss)	$ (7,383)	$ 94
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation and amortization	8,241	9,832
Stock-based compensation expense	3,974	3,216
Loss (gain) on sale of equipment	(22)	0
Deferred income taxes	(5)	(1,121)
Changes in operating assets and liabilities:
Trade receivables, net	1,195	7,044
Inventories, net	17,244	11,591
Prepaids and other assets	(4,076)	3,051
Accounts payable and accrued expenses	(7,403)	(22,231)
Other, net	(377)	0
Net cash (used in) provided by operating activities	11,388	11,476
Investing activities
Purchase of property, plant and equipment	(10,571)	(4,847)
Proceeds from sale of equipment	71	439
Acquisition of business, net of cash acquired	0	(19,869)
Net cash used in investing activities	(10,500)	(24,277)
Financing activities
Proceeds from exercise of stock options	52	403
Net cash provided by financing activities	52	403
Effect of exchange rate changes on cash activities	1,471	3,091
Increase (decrease) in cash and cash equivalents	2,411	(9,307)
Cash and cash equivalents at beginning of period	493,180	423,497
Cash and cash equivalents at end of period	$ 495,591	$ 414,190