Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Current assets
Cash and cash equivalents	$ 131,204	$ 101,436
Short-term investments	218,809	314,691
Prepaid expenses and other current assets	7,486	7,709
Total current assets	357,499	423,836
Property and equipment, net	19,801	15,743
Operating lease right-of-use assets	51,981	417
Long-term investments	10,077	14,153
Restricted cash and other	1,968	1,945
Total assets	441,326	456,094
Current liabilities
Accounts payable	5,573	6,237
Accrued liabilities	32,236	41,292
Operating lease liabilities - current	7,851	383
Total current liabilities	45,660	47,912
Operating lease liability	44,658
Other long-term liabilities	1,908	1,908
Total liabilities	92,226	49,820
Commitments and contingencies (Note 7)
Stockholders’ equity
Preferred stock, $0.0001 par value; 5,000,000 shares authorized; none issued and outstanding	0	0
Common stock, $0.0001 par value, 150,000,000 shares authorized at March 31, 2020 and December 31, 2019; 46,612,186 and 46,379,073 shares issued and outstanding at March 31, 2020 and December 31, 2019, respectively	5	5
Additional paid-in capital	897,058	884,486
Accumulated other comprehensive income	671	549
Accumulated deficit	(548,634)	(478,766)
Total stockholders’ equity	349,100	406,274
Total liabilities and stockholders’ equity	$ 441,326	$ 456,094