Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 15,044	$ 61,661
Short-term investments	194,645	249,127
Accounts receivable, net of allowances of $4	4,406	4,825
Inventory	2,142	1,948
Prepaid expenses and other current assets	3,954	4,434
Total current assets	220,191	321,995
Property and equipment, net of accumulated depreciation and amortization of $59,459 and $58,623, respectively	16,772	17,687
Goodwill	44,543	44,543
Other intangible assets, net of accumulated amortization of $2,354 and $1,471, respectively	51,002	51,885
Other assets	429	429
Total assets	332,937	436,539
Current liabilities:
Accounts payable	50,451	57,652
Accrued liabilities	12,865	12,282
Current portion of deferred revenue	5,124	40,099
Current portion of long-term debt, net of deferred issuance costs	12,896	14,094
Total current liabilities	81,336	124,127
Deferred revenue, net of current portion	18,195	22,428
Long-term debt, net of deferred issuance costs	232,198	231,576
Deferred tax liabilities	6,014	6,014
Other long-term liabilities	265	292
Total liabilities	338,008	384,437
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; 106,115 and 105,711 shares issued, respectively	106	106
Additional paid-in capital	1,441,890	1,435,526
Accumulated deficit	(1,443,973)	(1,381,404)
Accumulated other comprehensive loss	(218)	(222)
Treasury stock, at cost, 236 and 122 shares, respectively	(2,876)	(1,904)
Total equity	(5,071)	52,102
Total liabilities and equity	$ 332,937	$ 436,539