Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Cash flows from operating activities
Net loss	$ (43,637)	$ (53,333)	$ (205)
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Depreciation and amortization	31,105	28,350	22,400
Stock-based compensation expense	14,142	8,206	17,076
Deferred taxes	(328)	792	(668)
Amortization of investment, debt and other	438	247	159
Loss (gain) on disposal of property and equipment	1,322	(1,746)	185
Loss (gain) on foreign currency hedges	2,220	(2,104)	1,640
Allowance for doubtful accounts	61	577	(382)
Write-down of inventories	6,133	8,349	2,983
Foreign currency remeasurement and other, net	(3,944)	2,583	(2,661)
Asset impairment charges	0	324	0
Change in assets and liabilities:
Accounts receivable	(7,874)	13,166	2,496
Inventories	7,368	(22,347)	(1,332)
Prepaid expenses and other assets	8,162	(11,409)	(11,184)
Accounts payable	(1,411)	(10,874)	23,111
Accrued and other liabilities	5,838	6,452	218
Net cash provided by (used in) operating activities	19,595	(32,767)	53,836
Cash flows from investing activities
Purchase of property, plant and equipment	(14,867)	(47,409)	(51,693)
Proceeds from sale of property, plant and equipment and other assets	32	21,809	179
Purchase of marketable securities	(920)	(52,062)	(82,728)
Proceeds from sale of marketable securities	5,000	52,272	63,841
Proceeds from maturity of marketable securities	750	6,458	23,148
Restricted cash payable related to asset sale	0	0	1,039
Settlement of foreign currency hedges	(1,776)	1,618	(1,599)
Net cash used in investing activities	(11,781)	(17,314)	(47,813)
Cash flows from financing activities
Proceeds from exercise of stock options and issuance of stock under ESPP	5,614	4,893	6,587
Tax withholding on restricted stock units	(954)	(998)	(615)
Payments for public stock offering, net of offering costs	0	(117)	(164)
Proceeds from bank loans	34,305	112,834	95,200
Repayment of bank and acquisition-related loans	(63,040)	(68,492)	(96,119)
Proceeds from issuance of notes payable	7,137	6,621	16,032
Repayment of notes payable	(3,732)	(11,639)	(18,007)
Proceeds from government grants	1,210	0	602
Net cash (used in) provided by financing activities	(19,460)	43,102	3,516
Effect of exchange rates on cash, cash equivalents and restricted cash	(680)	1,958	(1,702)
Net increase (decrease) in cash, cash equivalents and restricted cash	(12,326)	(5,021)	7,837
Cash, cash equivalents, restricted cash and restricted cash equivalents, beginning of period	81,564	86,585	78,748
Cash, cash equivalents, restricted cash and restricted cash equivalents, end of period	69,238	81,564	86,585
Supplemental disclosure of cash flow information:
Cash paid for interest	1,600	732	263
Net cash paid (received) for income taxes	(1,383)	5,388	2,215
Supplemental disclosure of noncash investing and financing activities:
Unpaid deferred offering costs	0	0	117
Decrease (increase) in unpaid property, plant and equipment	8,548	6,072	(13,629)
Capital lease	362	0	0
Asset retirement obligation	$ 0	$ 2,146	$ 0