CONDENSED BALANCE SHEETS (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Current Assets:
Cash and cash equivalents	$ 23,534	$ 188,356
Investment securities, available-for-sale	141,644
Prepaid expenses and other current assets (including related party amounts of $0 and $28, respectively)	3,554	1,688
Total current assets	168,732	190,044
Operating lease right-of-use asset (including related party amounts of $2,013 and $0, respectively)	3,003
Property and equipment, net	1,628	1,382
Other assets	30	80
Total assets	173,393	191,506
Current Liabilities:
Accounts payable	884	2,228
Accrued liabilities (including related party amounts of $274 and $123, respectively)	6,122	4,814
Lease liability, current (including related party amounts of $151 and $0, respectively)	403
Total current liabilities	7,409	7,042
Lease liability, noncurrent (including related party amounts of $1,974 and $0, respectively)	2,818
Deferred rent (including related party amounts of $0 and $72, respectively)		104
Total liabilities	10,227	7,146
Commitments and contingencies (Note 8)
Stockholders’ equity:
Common stock, $0.001 par value; authorized shares 200,000,000 at June 30, 2019 and December 31, 2018, respectively; issued shares — 32,263,757 and 32,103,953 at June 30, 2019 and December 31, 2018, respectively; outstanding shares— 31,711,124 and 31,394,830 at June 30, 2019 and December 31, 2018, respectively	32	31
Additional paid-in capital	255,605	253,807
Accumulated deficit	(92,699)	(69,478)
Accumulated other comprehensive income	228
Total stockholders’ equity	163,166	184,360
Total liabilities and stockholders’ equity	$ 173,393	$ 191,506