CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Operating activities:
Net income	$ 6,422	$ 68,235
Adjustments to reconcile net income to net cash provided by operating activities:
Lower of cost or market reserve adjustment to inventory	5,546	1,365
Depreciation and amortization	21,807	14,332
Deferred income taxes, net	(5,734)	(2,495)
Loss (gain) on disposal of assets	(5)	51
Share-based compensation	8,362	5,849
Unrealized foreign exchange gain	(580)	(308)
Changes in operating assets and liabilities:
Accounts receivable, trade	27,822	(23,261)
Prepaid income tax	653
Inventories	(41,288)	(21,113)
Other current assets	(2,013)	(6,062)
Accounts payable	10,082	14,618
Accrued income taxes	(7,390)	4,360
Accrued liabilities	1,941	1,927
Net cash provided by operating activities	25,625	57,498
Investing activities:
Purchase of short-term investments	(15,023)
Maturities of short-term investments	9,036	8
Purchase of property, plant and equipment	(52,268)	(46,529)
Purchase of land use rights	(5,591)
Proceeds from disposal of equipment	697	171
Deposits and prepaid for equipment	(7,533)	(2,369)
Purchase of intangible assets	(343)	(407)
Net cash used in investing activities	(71,025)	(49,126)
Financing activities:
Proceeds from issuance of notes payable and long-term debt	35,899
Principal payments of long-term debt and notes payable	(1,883)	(38,300)
Proceeds from line of credit borrowings	113,266	36,000
Repayments of line of credit borrowings	(125,678)
Repayments of bank acceptance payable		(307)
Exercise of stock options	120	1,399
Payments of tax withholding on behalf of employees related to share-based compensation	(3,788)	(8,490)
Proceeds from common stock offering, net		21,572
Net cash provided by financing activities	17,936	11,874
Effect of exchange rate changes on cash	1,591	(208)
Net increase (decrease) in cash, cash equivalents and restricted cash	(25,873)	20,038
Cash, cash equivalents and restricted cash at beginning of period	83,948	51,964
Cash, cash equivalents and restricted cash at end of period	58,075	72,002
Cash paid for:
Interest	525	730
Income taxes	8,433	4,992
Non-cash investing and financing activities:
Net change in accounts payable related to property and equipment additions	$ 1,524	$ (1,091)