Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Cash flows from operating activities:
Net loss	$ (24,215)	$ (3,698)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	2,933	1,213
Stock-based compensation	4,619	3,753
Change in fair value of contingent consideration related to acquisition	200	(8,028)
Accretion of interest on convertible note	1,749	1,622
Amortization of deferred financing costs	232	198
Non-cash foreign exchange gain	(655)	(212)
Changes in operating assets and liabilities:
Accounts receivable and other receivables	(3,195)	(2,108)
Inventories	739	(8,793)
Prepaid expenses and other current assets	413	(1,283)
Accounts payable	2,692	3,855
Accrued payroll	(1,689)	1,224
Accrued expenses and other liabilities	(207)	2,097
Net cash used in operating activities	(16,384)	(10,160)
Cash flows from investing activities:
Purchases of marketable securities	(37,122)	(74,114)
Maturities of marketable securities	62,690	25,585
Purchases of property and equipment	(3,146)	(5,743)
Net cash provided by (used in) investing activities	22,422	(54,272)
Cash flows from financing activities:
Proceeds from sale of common stock under employee stock purchase plan	1,631	1,446
Proceeds from exercise of stock options	2,628	1,094
Minimum tax withholding paid on behalf of employees for restricted stock units	(291)	(1,395)
Net cash provided by financing activities	3,968	1,145
Effect of exchange rate changes on cash and cash equivalents	(535)	(22)
Net increase (decrease) in cash and cash equivalents	9,471	(63,309)
Cash and cash equivalents, beginning of period	26,798	95,152
Cash and cash equivalents, end of period	36,269	31,843
Supplemental disclosure of cash flow information:
Cash paid for interest	973	1,045
Cash paid for income taxes	140	207
Non-cash investing and financing activities:
Landlord funded leasehold improvements	46	3,870
Fair value of Nellix Milestone Shares (note 9)	0	38,372
Acquisition of property and equipment included in accounts payable	$ 71	$ 1,403