Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 20,365	$ 24,182
Marketable securities	64,878	83,250
Prepaid expenses	2,462	1,884
Other current assets	1,098	489
Total current assets	88,803	109,805
Property and equipment, net	4,509	4,595
Operating lease right-of-use asset	3,929
Other assets	282	282
Total assets	97,523	114,682
Current liabilities:
Accounts payable	824	193
Accrued liabilities	3,560	2,678
Operating lease liabilities, current	868
Deferred rent, current		354
Other liabilities, current	75	112
Total current liabilities	5,327	3,337
Operating lease liabilities, noncurrent	5,699
Deferred rent		2,548
Total liabilities	11,026	5,885
Stockholders' equity:
Common stock, $0.001 par value, 125,000,000 shares authorized as of September 30, 2019 (unaudited) and December 31, 2018; 19,141,645 and 19,114,421 shares issued and outstanding as of September 30, 2019 (unaudited) and December 31, 2018, respectively	19	19
Preferred stock, $0.001 par value, 10,000,000 shares authorized as of September 30, 2019 (unaudited) and December 31, 2018; zero shares issued and outstanding as of September 30, 2019 (unaudited) and December 31, 2018
Additional paid-in capital	161,405	158,176
Accumulated other comprehensive loss	(224)	(203)
Accumulated deficit	(74,703)	(49,195)
Total stockholders' equity	86,497	108,797
Total liabilities and stockholders' equity	$ 97,523	$ 114,682