Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 36,532	$ 63,617
Marketable securities	34,985	79,402
Accounts receivable	13,645	8,206
Receivable due from Roche	4,082	2,007
Inventory	8,922	10,438
Prepaid expenses and other current assets	5,102	5,251
Total current assets	103,268	168,921
Property and equipment, net	38,713	41,486
Restricted cash	2,305	1,395
Other assets	2,080	2,233
Total assets	146,366	214,035
Current liabilities:
Accounts payable	15,175	11,898
Accrued expenses and other current liabilities	25,269	20,578
Deferred revenue	1,926	2,104
Roche related-party deferred revenue	3,742	3,747
Current portion of deferred rent	1,384	2,324
Total current liabilities	47,496	40,651
Deferred rent, net of current portion and other non-current liabilities	9,354	8,538
Commitments and contingencies (Note 15)
Stockholders’ equity:
Common stock, $0.0001 par value, 150,000,000 shares authorized; 35,938,814 and 35,281,001 shares issued and outstanding at June 30, 2017 and December 31, 2016, respectively	4	4
Additional paid-in capital	525,041	509,664
Accumulated other comprehensive loss	65	(14)
Accumulated deficit	(435,594)	(344,808)
Total stockholders’ equity	89,516	164,846
Total liabilities and stockholders’ equity	$ 146,366	$ 214,035