Consolidated Statements of Cash Flows $ in Thousands	12 Months Ended
	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
OPERATING ACTIVITIES
Net loss	$ (13,808)	$ (6,079)	$ (7,074)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation, amortization and other	22,796	23,386	28,365
Stock-based compensation expense	7,986	7,419	6,724
Impairment loss	0	0	3,558
Amortization of debt discount and deferred issuance costs	5,891	5,664	629
Change in fair value of acquisition contingencies	(485)	(88)	(910)
Change in fair value of acquisition contingencies	(2,603)	(4,027)	(2,744)
Gain on extinguishment of Convertible Senior Notes	(421)	0	0
Excess tax benefit from share-based compensation	0	(571)	0
Excess tax benefit from share-based compensation
Accounts receivable	(6,265)	16,060	(4,547)
Inventories	859	(1,637)	2,862
Prepaid expenses and other current and non-current assets	(552)	(1,039)	787
Restricted cash	63	3,064	(2,158)
Accounts payable	4,323	(3,082)	4,380
Accrued payroll and related expenses	(375)	1,061	1,247
Income taxes payable	48	(64)	(1,036)
Deferred grant revenue	(3,658)	(2,672)	4,301
Other current and non-current liabilities	(1,984)	(1,086)	1,302
Net cash provided by operating activities	11,815	36,309	35,686
INVESTING ACTIVITIES
Acquisitions of property, equipment and intangibles	(11,909)	(17,032)	(11,241)
Acquisition of Immutopics, net of cash acquired	(5,061)	0	0
Net cash used for investing activities	(16,970)	(17,032)	(11,241)
FINANCING ACTIVITIES
Proceeds from issuance of Convertible Senior Notes	0	0	172,500
Proceeds from issuance of common stock	8,575	2,911	4,781
Payments of debt issuance costs	0	(365)	(4,712)
Excess tax benefit from share-based compensation	0	571	0
Payments on lease obligation	(540)	(509)	(441)
Repurchases of common stock	(20,168)	(30,934)	(1,956)
Repayments of Convertible Debt	(4,459)	0	0
Payments on acquisition contingencies	(207)	(129)	(2,112)
Payment for acquisition holdback	0	(229)	0
Net cash (used for) provided by financing activities	(16,799)	(28,684)	168,060
Effect of exchange rate changes on cash	(9)	(17)	2
Net (decrease) increase in cash and cash equivalents	(21,963)	(9,424)	192,507
Cash and cash equivalents, beginning of period	191,471	200,895	8,388
Cash and cash equivalents, at end of period	169,508	191,471	200,895
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION
Cash paid during the period for interest	6,488	6,998	981
Cash paid during the period for income taxes	490	1,922	327
NON-CASH INVESTING ACTIVITIES
Purchase of property, equipment and intangibles by incurring current liabilities	3,280	239	900
NON-CASH FINANCING ACTIVITIES
Decrease of accrued payroll and related expenses upon issuance of common stock	539	408	663
Receivable for stock option exercises	251	0	0
Debt issuance costs by incurring current liabilities	$ 0	$ 0	$ 365