CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 115,128	$ 36,308
Marketable securities	26,048	121,140
Accounts receivable		25,000
Prepaid expenses and other current assets	4,011	2,719
Total current assets	145,187	185,167
Property and equipment, net	3,690	4,171
Operating lease right-of-use asset	3,924	4,447
Restricted cash	2,498	2,498
Other long-term assets	1,061	98
Total assets	156,360	196,381
Current liabilities:
Accounts payable	2,680	1,130
Accrued expenses	8,233	9,610
Operating lease liability	1,272	1,135
Deferred revenue	20,362	20,923
Other current liabilities	20	16
Total current liabilities	32,567	32,814
Long-term portion of operating lease liability	3,490	4,168
Other long-term liabilities	9	9
Long-term portion of deferred revenue	38,120	46,489
Total liabilities	74,186	83,480
Commitments and contingencies (Note 7)
Stockholders' equity:
Preferred stock, $0.001 par value; 10,000,000 shares authorized at June 30, 2020 and December 31, 2019; no shares issued and outstanding at June 30, 2020 and December 31, 2019
Common stock, $0.001 par value; 150,000,000 shares authorized and 29,874,687 shares issued and outstanding as of June 30, 2020; 150,000,000 shares authorized and 29,792,922 shares issued and outstanding as of December 31, 2019	30	30
Additional paid-in capital	276,294	270,682
Accumulated other comprehensive income	49	37
Accumulated deficit	(194,199)	(157,848)
Total stockholders' equity	82,174	112,901
Total liabilities and stockholders' equity	$ 156,360	$ 196,381