Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 221,172	$ 171,017
Short-term investments	156,706	203,210
Prepaid expenses and other current assets	6,638	3,506
Total current assets	384,516	377,733
Property and equipment, net	1,495	1,618
Long-term investments	14,321	54,305
Other long-term assets	1,354	1,481
Restricted cash	60	60
Total assets	401,746	435,197
Current liabilities:
Accounts payable	6,289	16,237
Accrued expenses	12,916	11,052
Notes payable, current portion	0	1,375
Other current liabilities	925	871
Total current liabilities	20,130	29,535
Other long-term liabilities	180	654
Stockholders’ equity:
Preferred stock, $0.001 par value, 10,000 shares authorized and no shares, issued or outstanding at June 30, 2020 and December 31, 2019, respectively	0	0
Common stock, $0.001 par value, 500,000 shares authorized, 27,287 shares and 27,255 shares issued and outstanding at June 30, 2020 and December 31, 2019, respectively	27	27
Additional paid in capital	654,492	648,669
Accumulated other comprehensive income	753	338
Accumulated deficit	(273,836)	(244,026)
Total stockholders’ equity	381,436	405,008
Total liabilities and stockholders’ equity	$ 401,746	$ 435,197