Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Operating activities
Net loss	$ (70,611)	$ (38,925)
Adjustments to reconcile net loss to cash used in operating activities:
Depreciation and amortization expense	7,523	6,121
Stock-based compensation	8,049	3,475
Provision for doubtful accounts on accounts receivable	171
Provision for inventory excess and obsolescence	105
Non-cash interest expense		13
Changes in operating assets and liabilities:
Accounts receivable	(348)	251
Inventory	(4,756)	(2,431)
Prepaid expenses and other current assets	(3,255)	(475)
Other assets	(615)	(246)
Accounts payable	4,269	1,407
Accrued expenses and other current liabilities	4,728	1,569
Deferred rent and other non-current liabilities	2,305	(236)
Deferred revenue	115	354
Net cash used in operating activities	(52,320)	(29,123)
Investing activities
Purchases of property and equipment	(18,911)	(7,760)
Increase in restricted cash	(531)
Net cash used in investing activities	(19,442)	(7,760)
Financing activities
Proceeds from issuance of common stock to Roche, net of issuance costs	245,387
Proceeds from issuance of restricted stock and stock option exercises	4,457	349
Payments of notes payable		(1,098)
Net cash provided by (used in) financing activities	249,844	(749)
Net increase (decrease) in cash and cash equivalents	178,082	(37,632)
Cash and cash equivalents at beginning of period	72,080	124,293
Cash and cash equivalents at end of period	250,162	86,661
Supplemental disclosure of cash flow information
Cash paid for interest		150
Supplemental disclosure of non-cash investing and financing activities
Acquisition of property and equipment included in accounts payable and accrued expenses	$ 5,705	$ 1,312