Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Cash flows from operating activities
Net loss	$ (77,830)	$ (43,993)	$ (30,351)
Adjustments to reconcile net loss to net cash (used in) provided by operating activities
Depreciation and amortization	11,404	13,637	12,660
Net loss on disposal of assets	47	734	550
Stock-based compensation	1,250	1,408	1,595
Long-lived asset impairment charge	39,597
Realized gain on investments		(258)
Deferred taxes	(39)	72	(5,166)
Excess tax benefits from stock-based compensation			114
Changes in operating assets and liabilities:
Accounts receivable	6,585	(4,752)	9,098
Inventories	73	11,312	12,979
Other inventory supplies	2,166	4,203	2,976
Prepaid expenses and other assets	275	(794)	1,571
Accounts payable	(247)	(637)	(4,472)
Accrued payroll	(323)	153	(510)
Corporate income and franchise taxes	(63)	80	(25)
Accrued real estate taxes	(41)	(56)	39
Advance payments	(1)	(398)	(364)
Accrued and other current liabilities	431	67	(282)
Net cash (used in) provided by operating activities	(16,716)	(19,222)	412
Cash flows from investing activities
Purchases of property and equipment	(941)	(6,842)	(8,721)
Proceeds from disposal of assets		15	141
Purchase of investments	(2,322)	(28,805)	(2,040)
Proceeds from sale of investments	14,000	22,700	11,390
Net cash provided by (used in) investing activities	10,737	(12,932)	770
Cash flows from financing activities
Proceeds from exercise of options	4	256	140
Restricted cash	13	(18)	6
Net change in short-term borrowings	1,500
Proceeds from public offering, net of issuance costs		34,957
Taxes paid related to net share settlement of equity awards	(8)	(55)
Excess tax benefits (Deficiency) from stock-based compensation			(114)
Net cash provided by financing activities	1,509	35,140	32
Net effect of currency translation	1,333	296	284
Net (decrease) increase in cash and cash equivalents	(3,137)	3,282	1,498
Cash and cash equivalents, beginning of year	24,353	21,071	19,573
Cash and cash equivalents, end of year	21,216	24,353	21,071
Supplemental disclosure of cash flow information
Cash paid for interest	$ 109	$ 95	$ 87