Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 24,681	$ 202,989
Short-term investments	452,465	318,363
Accounts receivable, net of allowances of $4	741	911
Prepaid expenses and other current assets	14,271	10,137
Total current assets	492,158	532,400
Property and equipment, net of accumulated depreciation and amortization of $58,339 and $59,428, respectively	20,753	21,227
Goodwill	44,543	44,543
Other intangible assets	53,357	53,357
Other assets	530	433
Total assets	611,341	651,960
Current liabilities:
Accounts payable	25,544	19,725
Accrued liabilities	23,615	24,757
Current portion of deferred revenue	70,764	76,499
Current portion of long-term debt, net of deferred issuance costs	2,020	1,976
Total current liabilities	121,943	122,957
Deferred revenue, net of current portion	102,699	109,151
Long-term debt, net of deferred issuance costs	100,550	100,960
Deferred tax liabilities	18,675	18,675
Other long-term liabilities	14,593	14,367
Total liabilities	$ 358,460	$ 366,110
Commitments and contingencies
Equity:
Preferred stock, $.01 par value; 5,000 shares authorized; no shares issued and outstanding	$ 0	$ 0
Common stock, $.001 par value; 225,000 shares authorized; 104,083 and 103,860 shares issued, respectively	104	104
Additional paid-in capital	1,399,665	1,397,646
Accumulated deficit	(1,143,817)	(1,108,934)
Accumulated other comprehensive gain (loss)	297	(219)
Treasury stock, at cost, 306 and 237 shares, respectively	(3,368)	(2,747)
Total equity	252,881	285,850
Total liabilities and equity	$ 611,341	$ 651,960