Condensed Consolidated Balance Sheets (unaudited) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
CURRENT ASSETS
Cash and cash equivalents	$ 70,628	$ 29,294
Marketable securities	2,947	3,768
Restricted cash	155	80
Accounts receivable - grant	1,625	1,697
Deferred offering costs		2,535
Prepaid expenses and other current assets	1,551	912
Total current assets	76,906	38,286
Property and equipment, net	377	348
Other non-current assets	18	20
TOTAL ASSETS	77,301	38,654
CURRENT LIABILITIES
Accounts payable	348	176
Accrued and other current liabilities	3,013	2,347
Total current liabilities	3,361	2,523
Other non-current liabilities	16	27
TOTAL LIABILITIES	3,377	2,550
Commitments and Contingencies (Note 10 and 12)
STOCKHOLDERS’ EQUITY (DEFICIT)
Preferred stock, $0.0001 par value; 10,000,000 shares and no shares authorized as of June 30, 2016 and December 31, 2015, respectively; no shares issued and outstanding as of June 30, 2016 and December 31, 2015, respectively
Common stock, $0.0001 par value; 500,000,000 shares and 25,000,000 shares authorized as of June 30, 2016 and December 31, 2015, respectively; 13,411,772 shares and 757,336 shares issued and outstanding as of June 30, 2016 and December 31, 2015, respectively	1	0
Additional paid-in capital	107,478	1,373
Accumulated other comprehensive income (loss)	1	(1)
Accumulated deficit	(33,556)	(23,579)
TOTAL STOCKHOLDERS’ EQUITY (DEFICIT)	73,924	(22,207)
TOTAL LIABILITIES, CONVERTIBLE PREFERRED STOCK, AND STOCKHOLDERS’ EQUITY (DEFICIT)	$ 77,301	38,654
Series A Convertible Preferred Stock
CURRENT LIABILITIES
Convertible preferred stock		13,573
Series B Convertible Preferred Stock
CURRENT LIABILITIES
Convertible preferred stock		$ 44,738