Consolidated Balance Sheets - USD ($)	Dec. 31, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents	$ 117,763,000	$ 72,080,000
Marketable securities	89,607,000
Accounts receivable, net of allowance of $171 and $0 at December 31, 2015 and 2014, respectively	7,362,000	9,894,000
Receivable due from Roche	403,000
Inventory	7,992,000	4,809,000
Prepaid expenses and other current assets	6,517,000	2,865,000
Total current assets	229,644,000	89,648,000
Marketable securities	24,939,000
Property and equipment, net	41,333,000	21,015,000
Restricted cash	1,395,000	864,000
Other assets	678,000	411,000
Total assets	297,989,000	111,938,000
Current liabilities:
Accounts payable	10,469,000	7,263,000
Accrued expenses and other current liabilities	12,822,000	7,414,000
Deferred revenue	717,000	340,000
Roche related-party deferred revenue	3,742,000
Current portion of deferred rent	2,146,000	1,429,000
Total current liabilities	29,896,000	16,446,000
Deferred rent, net of current portion and other non-current liabilities	$ 10,404,000	$ 9,323,000
Commitments and contingencies (Note 12 )
Stockholders' equity:
Preferred stock, $0.0001 par value, 5,000,000 authorized; no shares issued and outstanding at December 31, 2015 and 2014
Common stock, $0.0001 par value, 150,000,000 shares authorized; 34,513,845 and 28,223,958 shares issued and outstanding at December 31, 2015 and 2014, respectively	$ 3,000	$ 3,000
Additional paid-in capital	489,480,000	228,151,000
Accumulated other comprehensive loss	(178,000)
Accumulated deficit	(231,616,000)	(141,985,000)
Total stockholders' equity	257,689,000	86,169,000
Total liabilities and stockholders' equity	$ 297,989,000	$ 111,938,000