Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Assets, Current
Cash and cash equivalents	$ 31,309	$ 7,035
Marketable securities	163,028
Prepaid Expense and Other Assets, Current	1,557	1,323
Total Current Assets	195,894	8,358
Property, Plant and Equipment, Net	3,234	2,804
Deposits and other non-current assets	321	335
Marketable securities	30,008
Total Assets	229,457	11,497
Liabilities, Current
Accounts Payable	612	1,554
Accrued expenses	3,430	642
Deferred rent, current portion	300	278
Deferred revenue, current portion	19,589
Total current liabilities	23,931	2,474
Deferred rent, net of current portion	1,015	1,314
Deferred revenue, net of current portion	35,393
Other non-current liabilities	44	255
Preferred stock tranche liability		6,305
Total Liabilities	60,383	10,348
Stockholders' Equity Attributable to Parent
Common stock, $0.001 par value: 105,000,000 and 65,000,000 shares authorized at December 31, 2015 and December 31, 2014 respectively; 24,930,979 and 814,834 shares issued and outstanding at December 31, 2015 and December 31, 2014, respectively	25	1
Additional Paid in Capital	219,122
Accumulated other comprehensive gain	(251)
Accumulated deficit	(49,822)	(20,831)
Total stockholders’ deficit	169,074	(20,830)
Total liabilities, redeemable convertible preferred stock and stockholders’ deficit	229,457	11,497
Redeemable Convertible Preferred Stock Series A
Liabilities, Current
Preferred stock tranche liability	$ 2,600
Redeemable convertible preferred stock		$ 21,979