Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
OPERATING ACTIVITIES:
Net income (loss)	$ 14,290	$ (3,446)
Adjustments to reconcile net income (loss) to net cash provided by (used for) operating activities:
Depreciation, amortization and other	5,690	6,123
Stock-based compensation expense	1,921	1,980
Amortization of debt discount and deferred issuance costs	1,365	1,429
Change in deferred tax assets and liabilities		(2,629)
Gain on extinguishment of Convertible Senior Notes		(421)
Changes in assets and liabilities:
Accounts receivable	4,048	(7,719)
Inventories	3,576	2,136
Income taxes receivable	2,063	119
Prepaid expenses and other current and non-current assets	(1,540)	(1,186)
Restricted cash	0	63
Accounts payable	(4,317)	1,150
Accrued payroll and related expenses	(1,493)	(3,290)
Income taxes payable	1,799	(167)
Deferred grant revenue	0	(1,746)
Other current and non-current liabilities	2,173	7
Net cash provided by (used for) operating activities:	29,575	(7,597)
INVESTING ACTIVITIES:
Acquisitions of property, equipment and intangibles	(3,712)	(2,001)
Acquisition of Immutopics, net of cash acquired	0	(5,094)
Net cash used for investing activities:	(3,712)	(7,095)
FINANCING ACTIVITIES:
Payments on lease obligation	(21)	(141)
Repurchases of common stock	(437)	(20,079)
Repurchases of Convertible Senior Notes	0	(4,459)
Proceeds from issuance of common stock	3,065	1,554
Payments on acquisition contingencies	(486)	(195)
Net cash provided by (used for) financing activities:	2,121	(23,320)
Effect of exchange rates on cash	2	(12)
Net increase (decrease) in cash and cash equivalents	27,986	(38,024)
Cash and cash equivalents, beginning of period	169,508
Cash and cash equivalents, end of period	197,494
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION:
Cash paid for interest	211	279
Income tax (refund) paid	(1,753)	103
NON-CASH INVESTING ACTIVITIES:
Purchase of property and equipment by incurring current liabilities	1,130	1,269
NON-CASH FINANCING ACTIVITIES:
Reduction of other current liabilities upon issuance of restricted share units	903	$ 539
Senior 3 Point 25 Percent Convertible Notes Due 2020 [Member] | Convertible Debt [Member]
Adjustments to reconcile net income (loss) to net cash provided by (used for) operating activities:
Gain on extinguishment of Convertible Senior Notes	(400)
FINANCING ACTIVITIES:
Repurchases of Convertible Senior Notes	$ (4,500)