Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Cash flows from operating activities
Net loss	$ (14,091)	$ (18,246)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation and amortization	8,851	8,005
Stock-based compensation expense	3,338	3,347
Deferred taxes	0	(42)
Others	109	116
Loss on sale of assets and other write-offs	85	2
Loss (gain) on foreign currency hedges	0	(1,557)
Allowance for doubtful accounts	0	(385)
Write-down of inventories	764	1,795
Amortization of operating lease right-of-use assets	432	0
Foreign currency remeasurement	1,818	2,299
Change in assets and liabilities, net of effects of asset sale:
Accounts receivable	9,675	(383)
Inventories	(1,654)	(1,744)
Prepaid expenses and other assets	2,804	5,107
Accounts payable	(1,232)	(2,208)
Accrued and other liabilities	(2,200)	438
Net cash provided by (used in) operating activities	8,699	(3,456)
Cash flows from investing activities
Purchase of property, plant and equipment	(3,600)	(8,293)
Proceeds from sale of property, plant and equipment and other assets	4	9
Purchase of marketable securities	(43)	(37)
Settlement of foreign currency hedges	0	1,566
Net cash used in investing activities	(3,639)	(6,755)
Cash flows from financing activities
Proceeds from exercise of stock options and issuance of stock under ESPP	157	124
Tax withholding on restricted stock units	(82)	(60)
Proceeds from bank loans, net of debt issuance costs	5,000	24,442
Repayment of bank loans	(5,764)	(21,844)
Proceeds from issuance of notes payable	0	698
Repayment of notes payable	(2,559)	(868)
Repayment of finance lease liabilities	(33)	0
Proceeds from government grants	0	472
Net cash (used in) provided by financing activities	(3,281)	2,964
Effect of exchange rates on cash, cash equivalents and restricted cash	353	272
Net increase (decrease) in cash, cash equivalents and restricted cash	2,132	(6,975)
Cash, cash equivalents and restricted cash at the beginning of the period	69,238	81,564
Cash, cash equivalents and restricted cash at the end of the period	71,370	74,589
Supplemental disclosure of non-cash investing and financing activities:
Decrease (increase) in unpaid property, plant and equipment	$ (257)	$ 6,447