Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Current assets
Cash and cash equivalents	$ 89,224	$ 39,560
Marketable securities	157,752
Restricted cash	769	222,294
Trade receivables, (including related parties of $4,910 and $4,653) net of allowance for doubtful accounts of $3,013 and $2,566	73,728	84,348
Prepaid expenses and other current assets (including related parties of $274 and $274)	9,732	6,260
Total current assets	331,205	352,462
Property and equipment, net of accumulated depreciation of $182,255 and $179,869	60,075	60,337
Intangible assets subject to amortization, net of accumulated amortization of $89,084 and $87,632 (including related parties of $9,248 and $9,555)	25,306	26,758
Intangible assets not subject to amortization	254,506	251,163
Goodwill	70,557	70,557
Other assets	4,253	4,690
Total assets	745,902	765,967
Current liabilities
Current maturities of long-term debt	3,000	3,000
Accounts payable and accrued expenses (including related parties of $2,645 and $2,548)	46,397	57,563
Deferred revenue	1,535	1,959
Total current liabilities	50,932	62,522
Long-term debt, less current maturities, net of unamortized debt issuance costs of $3,637 and $3,761	291,863	292,489
Other long-term liabilities	23,420	21,447
Deferred income taxes	39,289	40,639
Total liabilities	405,504	417,097
Commitments and contingencies (note 5)
Stockholders' equity
Additional paid-in capital	882,935	888,650
Accumulated deficit	(541,538)	(539,730)
Accumulated other comprehensive income (loss)	(1,009)	(60)
Total stockholders' equity	340,398	348,870
Total liabilities and stockholders' equity	745,902	765,967
Class A common stock
Stockholders' equity
Common stock	7	7
Class B common stock
Stockholders' equity
Common stock	2	2
Class U common stock
Stockholders' equity
Common stock	$ 1	$ 1

Sum of the carrying values as of the balance sheet date of obligations incurred through that date and due within one year (or the operating cycle, if longer), including liabilities incurred (and for which invoices have typically been received) and payable to vendors for goods and services received, taxes, interest, rent and utilities, accrued salaries and bonuses, payroll taxes and fringe benefits.

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Balance Type:	credit
Period Type:	instant

- Definition

Amount due from customers or clients, within one year of the balance sheet date (or the normal operating cycle, whichever is longer), for goods or services (including trade receivables) that have been delivered or sold in the normal course of business, reduced to the estimated net realizable fair value by an allowance established by the entity of the amount it deems uncertain of collection.