CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Current Assets:
Cash and cash equivalents	$ 82,648	$ 32,337
Short term deposits and investments	1,900	4,125
Restricted cash	407	133
Accounts receivable	1,961	824
Prepaid expenses and other current assets	2,131	1,494
Total current assets	89,047	38,913
Property and equipment, net	1,954	2,029
Restricted cash and other deposits	316	316
Other assets		1,566
Total assets	91,317	42,824
Current liabilities:
Accounts payable	943	2,179
Accrued expenses	4,715	3,378
Loans payable, current portion	1,781
Deferred revenue, current portion	1,242	1,313
Contingently repayable grant funding	258	420
Total current liabilities	8,939	7,290
Non-current liabilities:
Deferred rent and lease incentive		105
Loans payable, net of current portion	10,128	11,855
Deferred revenue, net of current portion	3,474	2,295
Other long-term liabilities		290
Total liabilities	22,541	21,835
Commitments and contingencies (Notes 7 and 12)
Redeemable convertiable preferred stock
Carrying value		137,482
Stockholders' equity (deficit):
Preferred stock, $0.0001 par value; 10,000,000 and 0 shares authorized; 0 and 0 shares issued and outstanding at June 30, 2016 and December 31, 2015, respectively.
Common stock, $0.0001 par value; 200,000,000 and 62,164,377 shares authorized at June 30, 2016 and December 31, 2015 respectively; 17,900,547 and 2,180,976 shares issued, 17,895,824 and 2,173,399 shares outstanding as of June 30, 2016 and December 31, 2015 respectively	1
Additional paid in capital	203,125	1
Accumulated deficit	(129,765)	(111,508)
Accumulated other comprehensive loss	(4,585)	(4,986)
Total stockholders' equity (deficit)	68,776	(116,493)
Total liabilities, redeemable convertible preferred stock and stockholders' equity (deficit)	91,317	42,824
Series A redeemable convertible preferred stock
Redeemable convertiable preferred stock
Carrying value		3,644
Series B redeemable convertible preferred stock
Redeemable convertiable preferred stock
Carrying value		21,448
Series C redeemable convertible preferred stock
Redeemable convertiable preferred stock
Carrying value		20,178
Series D redeemable convertible preferred stock
Redeemable convertiable preferred stock
Carrying value		42,902
Series SRN redeemable convertible preferred stock
Redeemable convertiable preferred stock
Carrying value	$ 5,000	12,082
Series E redeemable convertible preferred stock
Redeemable convertiable preferred stock
Carrying value		$ 37,228