Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 36,111	$ 40,401
Marketable securities	4,565	40,214
Accounts receivable, net	27,716	33,350
Prepaid expenses and other current assets	8,388	8,235
Total current assets	76,780	122,200
Property and equipment, net	406,328	380,243
Operating lease right-of-use assets, net	12,876	15,196
Goodwill	58,579	58,579
Intangible assets, net	10,652	14,940
Other assets	11,264	9,309
Total assets	576,479	600,467
Current liabilities:
Accounts payable	22,489	24,298
Accrued expenses and other liabilities	55,984	65,152
Deferred revenue	65,292	61,229
Current portion of operating leases	2,632	2,695
Current portion of long-term debt	778	778
Current portion of finance leases	573	2,721
Current portion of notes payable	95	1,527
Total current liabilities	147,843	158,400
Deferred revenue, net of current portion	159,462	166,660
Long-term portion of operating leases	14,487	17,357
Long-term debt	171,695	162,708
Long-term portion of finance leases	0	572
Long-term portion of notes payable		95
Deferred tax liabilities	984	993
Other liabilities	87	201
Total liabilities	494,558	506,986
Commitments and contingencies (Note 17)
Stockholders' equity:
Preferred stock, $0.0001 par value; 5,000 shares authorized; no shares issued and outstanding	0	0
Common stock, $0.0001 par value; 100,000 shares authorized; 44,631 and 44,224 shares issued and outstanding for 2020 and 2019, respectively	4	4
Additional paid-in capital	241,868	234,638
Accumulated deficit	(158,066)	(140,973)
Accumulated other comprehensive loss	(2,279)	(1,426)
Total common stockholders' equity	81,527	92,243
Non-controlling interests	394	1,238
Total stockholders' equity	81,921	93,481
Total liabilities and stockholders' equity	$ 576,479	$ 600,467