Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Cash flows from operating activities
Net income (loss)	$ (11,522)	$ 2,310
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Depreciation and amortization	6,185	5,453
Stock-based compensation expense	1,872	3,439
Deferred taxes	548	5
Amortization of investment, debt and other	76	28
(Gain) loss on sale of assets and other disposals	(1,687)	31
Gain on foreign currency hedges	(652)
Allowance for doubtful accounts	80	(339)
Write-down of inventories	196	742
Foreign currency remeasurement and other, net	38	565
Change in assets and liabilities, net of effects of acquisitions:
Accounts receivable	9,826	(3,628)
Inventories	(19,260)	3,037
Prepaid expenses and other assets	3,106	(2,122)
Accounts payable	(3,912)	3,178
Accrued and other liabilities	(3,642)	(7,515)
Net cash provided by (used in) operating activities	(18,748)	5,184
Cash flows from investing activities
Purchase of property, plant and equipment	(17,570)	(4,650)
Proceeds from sale of property, plant and equipment and other assets	21,745	6
Purchase of marketable securities	(38,806)	(32,045)
Proceeds from sale of marketable securities	45,286	15,516
Proceeds from maturity of marketable securities	6,458	1,500
Change in restricted cash	402	18
Settlement of foreign currency hedges	616
Net cash provided by (used in) investing activities	18,131	(19,655)
Cash flows from financing activities
Proceeds from exercise of stock options and issuance of stock under ESPP	499	1,233
Tax withholding on restricted stock units	(37)	(34)
Payments for public stock offering	(117)
Proceeds from bank loans, net of debt issuance costs	23,625	23,800
Repayment of bank loans	(24,020)	(24,017)
Proceeds from issuance of notes payable	2,966	4,984
Repayment of notes payable	(3,722)	(5,047)
Net cash provided by (used in) financing activities	(806)	919
Effect of exchange rates on cash and cash equivalents	622	203
Net decrease in cash and cash equivalents	(801)	(13,349)
Cash and cash equivalents at the beginning of the period	82,500	76,088
Cash and cash equivalents at the end of the period	81,699	62,739
Supplemental disclosure of noncash investing and financing activities:
Increase in unpaid property, plant and equipment	$ (1,226)	$ (1,355)