Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 61,661	$ 46,600
Short-term investments	249,127	299,904
Accounts receivable, net of allowances of $4	4,825	7,492
Inventory	1,948	0
Prepaid expenses and other current assets	4,434	3,878
Total current assets	321,995	357,874
Property and equipment, net of accumulated depreciation and amortization of $58,623 and $59,875, respectively	17,687	19,390
Goodwill	44,543	44,543
Other intangible assets	51,885	53,357
Other assets	429	461
Total assets	436,539	475,625
Current liabilities:
Accounts payable	57,652	52,877
Accrued liabilities	12,282	32,114
Current portion of deferred revenue	40,099	63,372
Current portion of long-term debt, net of deferred issuance costs	14,094	16,280
Total current liabilities	124,127	164,643
Deferred revenue, net of current portion	22,428	48,934
Long-term debt, net of deferred issuance costs	231,576	85,167
Deferred tax liabilities	6,014	18,675
Other long-term liabilities	292	805
Total liabilities	384,437	318,224
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; 105,711 and 104,582 shares issued, respectively	106	105
Additional paid-in capital	1,435,526	1,411,222
Accumulated deficit	(1,381,404)	(1,250,363)
Accumulated other comprehensive loss	(222)	(195)
Treasury stock, at cost, 122 and 306 shares, respectively	(1,904)	(3,368)
Total equity	52,102	157,401
Total liabilities and equity	$ 436,539	$ 475,625