Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Assets, Current
Cash and cash equivalents, fair value	$ 36,641	$ 31,309
Marketable securities	137,777	163,028
Prepaid Expense and Other Assets, Current	4,368	1,557
Total Current Assets	178,786	195,894
Property, Plant and Equipment, Net	7,893	3,234
Deposits and other non-current assets	1,527	321
Marketable securities	1,360	30,008
Total Assets	189,566	229,457
Liabilities, Current
Accounts Payable	550	612
Accrued expenses	6,488	3,430
Deferred rent, current portion		300
Deferred revenue, current portion	6,764	19,589
Total current liabilities	13,802	23,931
Deferred rent, net of current portion	4,999	1,015
Deferred revenue, net of current portion	34,818	35,393
Other non-current liabilities	25	44
Total Liabilities	53,644	60,383
Stockholders' Equity Attributable to Parent
Common stock, $0.001 par value: 120,000,000 shares authorized; 25,597,912 and 24,930,979 shares issued and outstanding at December 31, 2016 and 2015, respectively	26	25
Additional Paid in Capital	225,963	219,122
Accumulated other comprehensive gain	(52)	(251)
Accumulated deficit	(90,015)	(49,822)
Total stockholders’ deficit	135,922	169,074
Total liabilities, redeemable convertible preferred stock and stockholders’ deficit	$ 189,566	$ 229,457