Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 24,622	$ 56,865
Short-term investments	21,916	32,907
Accounts and other receivables, net	806	1,382
Prepaid expenses and other current assets	736	2,876
Total current assets	48,080	94,030
Property and equipment, net	3,150	4,016
Deferred income tax assets	401	359
Prepaid income taxes	0	4,997
Other assets, net	344	365
Total assets	51,975	103,767
Current liabilities:
Accounts payable	6,647	5,951
Accrued compensation	4,133	4,753
Other current liabilities	3,896	4,409
Deferred revenue	4,424	5,909
Total current liabilities	19,100	21,022
Long-term deferred revenue	22,303	26,393
Other long-term liabilities	915	1,012
Total liabilities	42,318	48,427
Commitments and contingencies (Notes 13 and 14)
Stockholders’ equity:
Common stock and additional paid-in capital – $0.001 par value; 100,000,000 shares authorized; 35,950,518 and 35,555,562 shares issued, respectively; 29,263,828 and 28,917,559 shares outstanding, respectively	228,046	221,098
Accumulated other comprehensive income	99	115
Accumulated deficit	(171,616)	(119,329)
Treasury stock at cost: 6,686,690 and 6,638,003 shares, respectively	(46,872)	(46,544)
Total stockholders’ equity	9,657	55,340
Total liabilities and stockholders’ equity	$ 51,975	$ 103,767