Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Current assets
Cash and cash equivalents	$ 186,587	$ 103,670
Short-term investments	8,879	8,091
Prepaid and other current assets	737	889
Total current assets	196,203	112,650
Property and equipment, net	5,961	3,014
Right-of-use asset	2,906
Other noncurrent assets	86	452
Total assets	205,156	116,116
Current liabilities
Accounts payable	896	888
Current portion of lease liability	438
Accrued expenses and other current liabilities	2,606	1,708
Total current liabilities	3,940	2,596
Lease liability	2,926
Other noncurrent liabilities		294
Total liabilities	6,866	2,890
Commitments and contingencies (Note 5)
Stockholders' equity
Preferred stock; $0.00001 par value; 20,000,000 shares authorized at June 30, 2019 (unaudited) and December 31, 2018; 2,061,773 shares issued, and no shares outstanding at June 30, 2019 (unaudited) and December 31, 2018	0	0
Common stock; $0.00001 par value; 80,000,000 shares authorized at June 30, 2019 (unaudited) and December 31, 2018; 16,945,069 and 14,428,916 shares issued and outstanding at June 30, 2019 (unaudited) and December 31, 2018, respectively	0	0
Additional paid-in capital	227,690	133,183
Accumulated other comprehensive income	18	2
Accumulated deficit	(29,418)	(19,959)
Total stockholders' equity	198,290	113,226
Total liabilities and stockholders' equity	$ 205,156	$ 116,116