Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Operating activities:
Consolidated net income (loss)	$ 13,048	$ 38	$ 24,939	$ (1,361)
Adjustments to reconcile consolidated net income (loss) to net cash provided by operating activities:
Depreciation and amortization	2,331	2,244	6,870	6,590
Stock-based compensation expense, net	688	731	2,604	1,272
Provision for doubtful accounts			91	8
Decrease in long-term income taxes payable				(5)
Increase in other long-term liabilities			7	90
Decrease in long-term deferred revenue			(54)	(53)
Gain on disposal of equipment			(45)	(15)
Deferred income taxes			26	17
Credit gain on available-for-sale securities	(2)	(3)	(6)	(9)
Change in current assets and liabilities, net			(11,590)	(5,896)
Net cash provided by operating activities			22,842	638
Investing activities:
Additions to property, plant and equipment			(6,894)	(10,164)
Proceeds from sale of equipment			45	15
Increase in other assets			(92)	(17)
Net cash used for investing activities			(6,941)	(10,166)
Financing activities:
Proceeds from issuance of Common Stock			8,378	2,510
Payment of contingent consideration obligations			(208)	(175)
Net cash provided by financing activities			8,170	2,335
Effect of foreign exchange rates on cash			(95)	(41)
Net increase (decrease) in cash and cash equivalents			23,976	(7,234)
Cash and cash equivalents at beginning of period	44,230	56,170	44,230	56,170
Cash and cash equivalents at end of period	$ 68,206	$ 48,936	$ 68,206	$ 48,936