Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents	$ 263,596	$ 72,080
Accounts receivable, net of allowance of $171 and $0 at June 30, 2015 and December 31, 2014, respectively	9,987	9,894
Receivable due from Roche	4,149
Inventories	6,142	4,809
Prepaid expenses and other current assets	5,675	2,865
Total current assets	289,549	89,648
Property and equipment, net	30,971	21,015
Restricted cash	1,395	864
Other assets	885	411
Total assets	322,800	111,938
Current liabilities:
Accounts payable	9,357	7,263
Accrued expenses and other current liabilities	10,752	7,414
Deferred revenue	127	340
Current portion of deferred rent	1,908	1,429
Total current liabilities	22,144	16,446
Deferred rent, net of current portion, and other non-current liabilities	11,092	9,323
Total liabilities	$ 33,236	$ 25,769
Commitments and contingencies (Note 13)
Stockholders' equity:
Preferred Stock, $0.0001 par value, 5,000,000 shares authorized; no shares issued and outstanding
Common stock, $0.0001 par value, 150,000,000 shares authorized; 34,281,377 and 28,223,958 shares issued and outstanding at June 30, 2015 and December 31, 2014, respectively	$ 3	$ 3
Additional paid-in capital	481,561	228,151
Accumulated deficit	(192,000)	(141,985)
Total stockholders' equity	289,564	86,169
Total liabilities and stockholders' equity	$ 322,800	$ 111,938