CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($)	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Cash flows from operating activities:
Net loss	$ (7,507,000)	$ (29,535,000)
Adjustments to reconcile net loss to cash provided by operating activities:
Depreciation and amortization (other than multi-client data library)	1,848,000	2,098,000
Amortization of multi-client data library	12,701,000	19,396,000
Stock-based compensation expense	1,094,000	2,831,000
Impairment of multi-client data library	1,167,000	0
Impairment of goodwill	4,150,000	0
Amortization of government relief funding expected to be forgiven	6,923,000	0
Deferred income taxes	338,000	(467,000)
Changes in operating assets and liabilities:
Accounts receivable	18,678,000	8,734,000
Unbilled receivables	(2,080,000)	21,575,000
Inventories	179,000	735,000
Accounts payable, accrued expenses and accrued royalties	(6,930,000)	(6,054,000)
Deferred revenue	(466,000)	(3,337,000)
Other assets and liabilities	102,000	(1,711,000)
Net cash provided by operating activities	16,351,000	14,265,000
Cash flows from investing activities:
Cash invested in multi-client data library	(14,596,000)	(14,782,000)
Purchase of property, plant and equipment	(697,000)	(1,412,000)
Net cash used in investing activities	(15,293,000)	(16,194,000)
Cash flows from financing activities:
Borrowings under revolving line of credit	27,000,000	0
Payments under revolving line of credit	(4,500,000)	0
Proceeds from government relief funding	6,923,000	0
Payments on notes payable and long-term debt	(1,527,000)	(1,406,000)
Other financing activities	5,000	(551,000)
Net cash provided by (used in) financing activities	27,901,000	(1,957,000)
Effect of change in foreign currency exchange rates on cash, cash equivalents and restricted cash	538,000	(102,000)
Net increase (decrease) in cash, cash equivalents and restricted cash	29,497,000	(3,988,000)
Cash, cash equivalents and restricted cash at beginning of period	33,118,000	33,854,000
Cash, cash equivalents and restricted cash at end of period	$ 62,615,000	$ 29,866,000