Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Current assets
Cash and cash equivalents	$ 48,705	$ 46,733
Marketable securities	107,486	132,424
Restricted cash	734	732
Trade receivables, (including related parties of $4,483 and $4,530) net of allowance for doubtful accounts of $2,799 and $3,395	68,809	79,308
Assets held for sale	950	1,179
Prepaid expenses and other current assets (including related parties of $274 and $274)	13,621	10,672
Total current assets	240,305	271,048
Property and equipment, net of accumulated depreciation of $185,731 and $187,375	79,392	64,939
Intangible assets subject to amortization, net of accumulated amortization of $98,373 and $93,793 (including related parties of $7,406 and $8,327)	18,019	22,598
Intangible assets not subject to amortization	251,098	254,598
Goodwill	46,511	74,292
Operating leases right of use asset	45,058
Other assets	7,459	2,934
Total assets	687,842	690,409
Current liabilities
Current maturities of long-term debt	3,000	3,000
Accounts payable and accrued expenses (including related parties of $2,277 and $1,948)	46,766	51,034
Operating lease liabilities	8,843
Total current liabilities	58,609	54,034
Long-term debt, less current maturities, net of unamortized debt issuance costs of $2,600 and $2,709	238,400	240,541
Long-term operating lease liabilities	42,672
Other long-term liabilities	7,531	16,418
Deferred income taxes	54,654	46,684
Total liabilities	401,866	357,677
Commitments and contingencies (note 6)
Stockholders' equity
Additional paid-in capital	841,567	862,299
Accumulated deficit	(555,236)	(528,164)
Accumulated other comprehensive income (loss)	(364)	(1,412)
Total stockholders' equity	285,976	332,732
Total liabilities and stockholders' equity	687,842	690,409
Class A common stock
Stockholders' equity
Common stock	6	6
Class B common stock
Stockholders' equity
Common stock	2	2
Class U common stock
Stockholders' equity
Common stock	$ 1	$ 1