Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Cash flows from operating activities
Net income (loss)	$ (20,863)	$ 4,986
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Depreciation and amortization	13,298	11,137
Stock-based compensation expense	3,758	5,669
Deferred taxes	609
Amortization of investment, debt and other	122	94
(Gain) loss on sale of assets and other write-offs	(1,669)	48
Gain on foreign currency hedges	(1,070)
Allowance for doubtful accounts	92	(393)
Write-down of inventories	2,279	1,740
Foreign currency remeasurement and other, net	650	248
Change in assets and liabilities, net of effects of acquisitions:
Accounts receivable	24,110	(3,288)
Inventories	(32,291)	1,892
Prepaid expenses and other assets	(14,803)	(501)
Accounts payable	2,451	8,224
Accrued and other liabilities	6,831	(6,678)
Net cash provided by (used in) operating activities	(16,496)	23,178
Cash flows from investing activities
Purchase of property, plant and equipment	(34,597)	(14,595)
Proceeds from sale of property, plant and equipment and other assets	21,784	19
Purchase of marketable securities	(41,807)	(47,807)
Proceeds from sale of marketable securities	52,271	34,682
Proceeds from maturity of marketable securities	6,458	8,000
Change in restricted cash	882	19
Settlement of foreign currency hedges	1,005
Net cash provided by (used in) investing activities	5,996	(19,682)
Cash flows from financing activities
Proceeds from exercise of stock options and issuance of stock under ESPP	3,136	3,538
Tax withholding on restricted stock units	(638)	(77)
Payments for public stock offering	(117)
Proceeds from bank loans, net of debt issuance costs	48,994	47,600
Repayment of bank loans	(48,045)	(48,047)
Proceeds from issuance of notes payable	4,235	9,217
Repayment of notes payable	(6,599)	(9,283)
Net cash provided by financing activities	966	2,948
Effect of exchange rates on cash and cash equivalents	695	(56)
Net increase (decrease) in cash and cash equivalents	(8,839)	6,388
Cash and cash equivalents at the beginning of the period	82,500	76,088
Cash and cash equivalents at the end of the period	73,661	82,476
Supplemental disclosure of noncash investing and financing activities:
Increase in unpaid property, plant and equipment	$ 6,342	$ (4,872)