Condensed Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Current assets:
Cash and cash equivalents	$ 24,365	$ 14,136
Short-term investments	56,980	56,976
Accounts and other receivables (net of allowances for doubtful accounts of $9)	769	598
Deferred income taxes	7,784	7,784
Prepaid expenses and other current assets	550	690
Total current assets	90,448	80,184
Property and equipment, net	1,154	944
Deferred income tax assets	28,046	29,066
Intangibles and other assets, net	362	381
Total assets	120,010	110,575
Current liabilities:
Accounts payable	1,949	682
Accrued compensation	2,198	4,680
Other current liabilities	2,492	1,653
Deferred revenue	23,380	8,920
Total current liabilities	30,019	15,935
Long-term deferred revenue	11,928	13,441
Other long-term liabilities	501	528
Total liabilities	42,448	29,904
Contingencies (Note 12)
Stockholders' equity:
Common stock and additional paid-in capital - $0.001 par value; 100,000,000 shares authorized; 33,943,787 and 33,619,766 shares issued, respectively; 28,355,624 and 28,637,022 shares outstanding, respectively	199,965	198,057
Accumulated other comprehensive income	113	112
Accumulated deficit	(85,065)	(86,929)
Treasury stock at cost: 5,588,163 and 4,982,744 shares, respectively	(37,451)	(30,569)
Total stockholders' equity	77,562	80,671
Total liabilities and stockholders' equity	$ 120,010	$ 110,575