Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
OPERATING ACTIVITIES
Net (loss) income	$ (6,079)	$ (7,074)	$ 7,390
Adjustments to reconcile net (loss) income to net cash provided by operating activities:
Depreciation, amortization and other	23,386	28,365	24,896
Stock-based compensation expense	7,419	6,724	8,771
Impairment loss	0	3,558	0
Amortization of debt discount and deferred issuance costs	5,664	629	337
Change in fair value of acquisition contingencies	(88)	(910)	80
Change in deferred tax assets and liabilities	(4,027)	(2,744)	(1,928)
Excess tax benefit from share-based compensation	(571)	0	(2,346)
Changes in assets and liabilities:
Accounts receivable	16,060	(4,547)	2,911
Inventories	(1,637)	2,862	(11,975)
Prepaid expenses and other current and non-current assets	(1,039)	787	(388)
Restricted cash	3,064	(2,158)	1,187
Accounts payable	(3,082)	4,380	(651)
Accrued payroll and related expenses	1,061	1,247	1,055
Income taxes payable	(64)	(1,036)	(3,523)
Deferred grant revenue	(2,672)	4,301	(127)
Other current and non-current liabilities	(1,086)	1,302	(7)
Net cash provided by operating activities	36,309	35,686	25,682
INVESTING ACTIVITIES
Acquisitions of property and equipment	(16,968)	(11,149)	(20,821)
Acquisition of BioHelix, net of cash acquired	0	0	(9,184)
Acquisition of AnDiaTec	0	0	(2,250)
Acquisition of intangibles	(64)	(92)	(1,680)
Net cash used for investing activities	(17,032)	(11,241)	(33,935)
FINANCING ACTIVITIES
Proceeds from issuance of Convertible Senior Notes	0	172,500	0
Proceeds from issuance of common stock, net of cancellations	2,911	4,781	7,928
Payments of debt issuance costs	(365)	(4,712)	0
Excess tax benefit from share-based compensation	571	0	2,346
Payments on lease obligation	(509)	(441)	(380)
Repurchases of common stock	(30,934)	(1,956)	(2,157)
Payments on line of credit	0	0	(5,000)
Payments on acquisition contingencies	(129)	(2,112)	(947)
Payment for acquisition holdback	(229)	0	0
Net cash (used for) provided by financing activities	(28,684)	168,060	1,790
Effect of exchange rate changes on cash	(17)	2	(5)
Net (decrease) increase in cash and cash equivalents	(9,424)	192,507	(6,468)
Cash and cash equivalents, beginning of period	200,895	8,388	14,856
Cash and cash equivalents, at end of period	191,471	200,895	8,388
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION
Cash paid during the period for interest	6,998	981	1,807
Cash paid during the period for income taxes	1,922	327	2,211
NON-CASH INVESTING ACTIVITIES
Purchase of capital equipment by incurring current liabilities	239	900	172
Lease incentive for tenant improvements	0	0	1,658
NON-CASH FINANCING ACTIVITIES
Decrease of accrued payroll and related expenses upon issuance of common stock	408	663	456
Debt issuance costs by incurring current liabilities	$ 0	$ 365	$ 0