CONDENSED CONSOLIDATED BALANCE SHEETS (UNAUDITED) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 143,372	$ 53,774
Short-term investments	91,557	208,614
Prepaid expenses and other current assets	3,404	4,189
Total current assets	238,333	266,577
Property and equipment, net	42,566	42,716
Right-of-use assets	6,615
Restricted cash	1,274	1,274
Total assets	288,788	310,567
Current liabilities:
Accounts payable	7,398	2,608
Accrued expenses and other liabilities	6,949	7,644
Operating lease liabilities	2,331
Deferred rent		1,313
Deferred revenue	774	809
Total current liabilities	17,452	12,374
Non-current liabilities:
Operating lease liabilities, net of current portion	14,821
Deferred rent, net of current portion		9,544
Deferred revenue, net of current portion	29,974	30,142
Total liabilities	62,247	52,060
Commitments and contingencies (Note 7)
Stockholders’ equity:
Preferred stock, $0.0001 par value, 10,000,000 shares authorized; no shares issued and outstanding
Common stock, $0.0001 par value; 200,000,000 shares authorized; 45,212,190 and 45,138,408 shares issued as of March 31, 2020 and December 31, 2019, respectively; and 45,206,066 and 45,116,742 shares outstanding as of March 31, 2020 and December 31, 2019, respectively	4	4
Additional paid-in capital	461,561	457,994
Accumulated other comprehensive gain (loss)	(19)	183
Accumulated deficit	(235,005)	(199,674)
Total stockholders’ equity	226,541	258,507
Total liabilities and stockholders' equity	$ 288,788	$ 310,567