Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Cash flows from operating activities:
Net loss	$ (7,254)	$ (2,340)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization (other than multi-client library)	959	840
Amortization of multi-client data library	3,285	8,020
Impairment of multi-client data library	0	1,167
Impairment of goodwill	0	4,150
Stock-based compensation expense	286	617
Provision for expected credit losses	396	0
Deferred income taxes	(7,743)	421
Change in operating assets and liabilities:
Accounts receivable	(798)	(21,868)
Unbilled receivables	7,177	2,666
Inventories	217	(772)
Accounts payable, accrued expenses and accrued royalties	(2,598)	1,688
Deferred revenue	823	355
Other assets and liabilities	973	(1,910)
Net cash used in operating activities	(4,277)	(6,966)
Cash flows from investing activities:
Investment in multi-client data library	(5,211)	(9,668)
Purchase of property, plant and equipment	(576)	(496)
Net cash used in investing activities	(5,787)	(10,164)
Cash flows from financing activities:
Borrowings under revolving line of credit	0	27,000
Repayments under revolving line of credit	(1,250)	0
Payments on notes payable and long-term debt	(752)	(760)
Costs associated with debt issuance	(806)	0
Net proceeds from issuance of stocks	9,802	0
Other financing activities	(316)	(10)
Net cash provided by financing activities	6,678	26,230
Effect of change in foreign currency exchange rates on cash, cash equivalents and restricted cash	128	470
Net increase (decrease) in cash, cash equivalents and restricted cash	(3,258)	9,570
Cash, cash equivalents and restricted cash at beginning of period	39,813	33,118
Cash, cash equivalents and restricted cash at end of period	$ 36,555	$ 42,688