CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 119,128	$ 24,622
Short-term investments	19,842	21,916
Accounts and other receivables	2,667	806
Prepaid expenses and other current assets	5,616	736
Total current assets	147,253	48,080
Property and equipment, net	2,903	3,150
Deferred income tax assets	371	401
Other assets	4,808	344
Total assets	155,335	51,975
Current liabilities:
Accounts payable	4,256	6,647
Accrued compensation	2,552	4,133
Other current liabilities	3,296	3,896
Deferred revenue	4,920	4,424
Total current liabilities	15,024	19,100
Long-term deferred revenue	33,665	22,303
Other long-term liabilities	1,374	915
Total liabilities	50,063	42,318
Contingencies (Note 12)
Stockholders’ equity:
Common stock and additional paid-in capital — $0.001 par value; 100,000,000 shares authorized; 37,043,975 and 35,950,518 shares issued, respectively; 30,357,285 and 29,263,828 shares outstanding, respectively	235,438	228,046
Accumulated other comprehensive income	104	99
Accumulated deficit	(83,398)	(171,616)
Treasury stock at cost: 6,686,690 shares	(46,872)	(46,872)
Total stockholders’ equity	105,272	9,657
Total liabilities and stockholders’ equity	$ 155,335	$ 51,975