Condensed Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Cash flows from operating activities:
Net loss	$ (16,068)	$ (35,774)	$ (28,730)
Adjustments to reconcile net loss to net cash used in operating activities:
Bad debt expense	204	325	62
Depreciation and amortization	2,351	2,183	2,729
Stock-based compensation	7,922	6,471	4,136
Change in fair value of contingent consideration related to acquisition	8,500	13,700	10,500
Business development	752	0	0
Accretion of interest on convertible note	175	0	0
Amortization of deferred financing costs	21	0	0
Gain on sale of equipment	0	0	(141)
Foreign Currency Transaction Gain (Loss), Unrealized	(1,731)	0	0
Changes in operating assets and liabilities:
Accounts receivable	(2,440)	(8,319)	(3,392)
Inventories	(1,046)	12	(9,801)
Prepaid expenses and other current assets	(769)	(408)	(153)
Accounts payable	(196)	199	700
Accrued payroll	3,546	1,255	1,597
Accrued expenses and other current liabilities	273	1,827	111
Net cash used in operating activities	1,494	(18,529)	(22,382)
Cash flows from investing activities:
Investment in marketable securities	(31,313)	0	0
Purchases of property and equipment	(2,862)	(2,238)	(3,033)
Purchases of patent license	0	(100)	0
Business acquisition	0	(1,156)	0
Net cash used in investing activities	(34,175)	(3,494)	(3,033)
Cash flows from financing activities:
Deferred financing costs	(3,657)	0	0
Proceeds from sale of common stock under secondary offering, net of expenses	0	40,069	0
Proceeds from sale of common stock under employee stock purchase plan	2,444	2,369	1,965
Proceeds from exercise of stock options	4,875	4,992	5,324
Funding of restricted cash account	5,395	0	0
Release of restricted cash account	(5,395)	0	0
Proceeds from convertible debt	86,250	0	0
Adjustments to Additional Paid in Capital, Equity Component of Convertible Debt	(7,418)	0	0
Net cash provided by financing activities	82,494	47,430	7,289
Effect of exchange rate changes on cash and cash equivalents	221	(324)	(30)
Net decrease in cash and cash equivalents	50,034	25,083	(18,156)
Cash and cash equivalents, beginning of period	45,118	20,035	38,191
Cash and cash equivalents, end of period	95,152	45,118	20,035
Supplemental Cash Flow Information [Abstract]
Cash paid for interest	16	10	32
Cash paid for income taxes	171	16	24
Non-cash investing and financing activities:
Landlord funded leasehold improvements	$ 1,485	$ 0	$ 0