Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($)	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Operating activities
Net loss	$ (37,415,000)	$ (46,453,000)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization expense	5,365,000	4,466,000
Stock-based compensation expense	3,208,000	6,399,000
Amortization of premiums and discounts on marketable securities		14,000
Gain on disposal of long-lived assets		(139,000)
Changes in operating assets and liabilities:
Accounts receivable	4,974,000	2,348,000
Receivable from Roche	1,059,000	(2,863,000)
Inventory	(3,230,000)	178,000
Prepaid expenses and other current assets	(3,143,000)	(30,000)
Other assets	108,000	82,000
Accounts payable	3,456,000	278,000
Accrued expenses and other current liabilities	(14,388,000)	(1,780,000)
Deferred rent and other non-current liabilities	(366,000)	(571,000)
Deferred revenue	499,000	(120,000)
Roche related-party deferred revenue	981,000	(3,453,000)
Net cash used in operating activities	(38,892,000)	(41,644,000)
Investing activities
Purchases of property and equipment	(5,682,000)	(3,863,000)
Purchases of marketable securities and other investments		(4,996,000)
Proceeds from maturities of marketable securities		34,390,000
Net cash (used in) provided by investing activities	(5,682,000)	25,531,000
Financing activities
Proceeds from indebtedness to Roche	30,000,000
Proceeds from stock option exercises	3,430,000	1,571,000
Net cash provided by financing activities	33,430,000	1,571,000
Net decrease in cash, cash equivalents, and restricted cash	(11,144,000)	(14,542,000)
Effect of exchange rate changes on cash and cash equivalents	33,000
Cash, cash equivalents, and restricted cash at beginning of period	73,709,000	65,012,000
Cash, cash equivalents, and restricted cash at end of period	62,598,000	50,470,000
Supplemental disclosure of non-cash investing and financing activities
Cash paid for interest	891,000	75,000
Acquisition of property and equipment included in accounts payable and accrued expenses	$ 4,528,000	$ 696,000