CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017
Current assets:
Cash and cash equivalents	$ 30,043	$ 52,056	$ 40,225
Accounts receivable, net	23,624	19,478
Unbilled receivables	25,724	37,304
Inventories	15,129	14,508
Prepaid expenses and other current assets	5,854	7,643
Total current assets	100,374	130,989
Deferred income tax asset	4,058	1,753
Property, plant, equipment and seismic rental equipment, net	49,968	52,153
Multi-client data library, net	83,254	89,300
Goodwill	23,590	24,089
Other assets	2,713	2,785
Total assets	263,957	301,069
Current liabilities:
Current maturities of long-term debt	1,335	40,024
Accounts payable	31,872	24,951
Accrued expenses	33,556	38,697
Accrued multi-client data library royalties	28,235	27,035
Deferred revenue	10,327	8,910
Total current liabilities	105,325	139,617
Long-term debt, net of current maturities	119,449	116,720
Other long-term liabilities	12,269	13,926
Total liabilities	237,043	270,263
Equity:
Common stock, $0.01 par value; authorized 26,666,667 shares; outstanding 14,002,999 and 12,019,701 shares at September 30, 2018 and December 31, 2017, respectively	140	120
Additional paid-in capital	951,811	903,247
Accumulated deficit	(906,749)	(854,921)
Accumulated other comprehensive loss	(19,591)	(18,879)
Total stockholders’ equity	25,611	29,567
Noncontrolling interest	1,303	1,239
Total equity	26,914	30,806
Total liabilities and equity	$ 263,957	$ 301,069