Condensed Consolidated Balance Sheets (unaudited) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 7,181	$ 7,042
Marketable securities	135,910	100,986
Prepaid expenses	1,563	1,491
Other current assets	24	15
Total current assets	144,678	109,534
Restricted cash	84	84
Property and equipment, net	318	321
Total assets	145,080	109,939
Current liabilities:
Accounts payable	3,364	2,989
Accrued liabilities	1,245	2,727
Total current liabilities	4,609	5,716
Other liabilities	15	19
Total liabilities	4,624	5,735
Commitments and contingencies (see Note 10)
Stockholders’ equity:
Common stock, $0.0001 par value, 150,000,000 shares authorized as of March 31, 2019 and December 31, 2018; 35,255,344 and 28,055,344 shares issued and outstanding as of March 31, 2019 and December 31, 2018, respectively; 35,254,844 and 28,054,344 shares vested as of March 31, 2019 and December 31, 2018, respectively	4	3
Additional paid-in capital	222,882	175,635
Accumulated deficit	(82,462)	(71,393)
Accumulated other comprehensive gain (loss)	32	(41)
Total stockholders’ equity	140,456	104,204
Total liabilities and stockholders’ equity	$ 145,080	$ 109,939