UNAUDITED CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 31,459	$ 48,460
Short-term investments	62,621	62,326
Accounts receivable	59	16
Unbilled revenue receivable	6	19
Prepaid expenses and other assets	2,684	1,955
Total current assets	96,829	112,776
Property and equipment, net	4,269	2,099
Right-of-use asset	8,768	356
Other noncurrent assets	1,414	32
Total assets	111,280	115,263
Current liabilities:
Current portion of long-term debt	0	4,965
Accounts payable	2,006	1,814
Accrued expenses and other current liabilities	2,124	2,435
Deferred revenue, current	8,479	21,873
Total current liabilities	12,609	31,087
Long-term debt, net	16,500	0
Common stock warrant liability, noncurrent	0	414
Deferred revenue, noncurrent	0	2,956
Lease liability, noncurrent	8,087	59
Other noncurrent liabilities	656	0
Total liabilities	37,852	34,516
Stockholders’ equity:
Common stock, $0.0001 par value per share; 200,000,000 shares authorized, 87,228,586 issued and outstanding, September 30, 2020; 86,069,263 issued and outstanding, December 31, 2019	9	9
Additional paid-in capital	166,499	162,062
Accumulated other comprehensive income (loss)	200	(27)
Accumulated deficit	(93,280)	(81,297)
Total stockholders' equity	73,428	80,747
Total liabilities and stockholders’ equity	$ 111,280	$ 115,263