CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 36,678	$ 11,725
Accounts receivable	15,589	69,720
Unbilled receivables	986	127
Inventory	15,381	19,136
Prepaid expenses and other current assets	14,032	11,378
Total current assets	82,666	112,086
Property, plant and equipment, net	263,119	274,676
Operating lease right-of-use assets	29,478	32,099
Intangible assets, net	7,659	8,253
Other assets	446	563
Total assets	383,368	427,677
Current liabilities:
Accounts payable	4,825	3,268
Accrued expenses and other liabilities	11,244	13,142
Deferred revenue, current	9,234	6,875
Long-term debt, net, current	7,281	6,901
Operating lease liabilities, current	7,405	7,077
Total current liabilities	39,989	37,263
Deferred revenue, net	7,215	3,482
Long-term debt, net	16,974	22,445
Operating lease liabilities, long-term	24,733	27,020
Deferred tax liabilities, long-term, net	25,438	32,981
Asset retirement obligation	16,291	14,996
Contingent consideration	0	180
Other Liabilities, Noncurrent	508	503
Total liabilities	131,148	138,870
Commitments and contingencies (Note 15)
Stockholders’ equity
Treasury stock, at cost, 1,716,805 and 1,618,265 shares at September 30, 2021 and December 31, 2020, respectively	42	42
Treasury stock, at cost, 1,716,805 and 1,618,265 shares at September 30, 2021 and December 31, 2020, respectively	(4,427)	(4,134)
Additional paid-in capital	173,426	171,209
Retained earnings	82,826	121,267
Accumulated other comprehensive income	353	423
Total stockholders’ equity	252,220	288,807
Total liabilities and stockholders’ equity	$ 383,368	$ 427,677