CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Cash flows from operating activities:
Net loss	$ (29,535)	$ (43,839)
Adjustments to reconcile net loss to cash provided by (used in) operating activities:
Depreciation and amortization (other than multi-client data library)	2,098	4,778
Amortization of multi-client data library	19,396	19,557
Stock-based compensation expense	2,831	2,043
Deferred income taxes	(467)	(1,866)
Changes in operating assets and liabilities:
Accounts receivable	8,734	3,896
Unbilled receivables	21,575	24,013
Inventories	735	(445)
Accounts payable, accrued expenses and accrued royalties	(6,054)	(10,629)
Deferred revenue	(3,337)	(445)
Other assets and liabilities	(1,711)	2,733
Net cash provided by (used in) operating activities	14,265	(204)
Cash flows from investing activities:
Investment in multi-client data library	(14,782)	(13,782)
Purchase of property, plant and equipment	(1,412)	(424)
Net cash used in investing activities	(16,194)	(14,206)
Cash flows from financing activities:
Payments under revolving line of credit	0	(10,000)
Payments on notes payable and long-term debt	(1,406)	(29,699)
Net proceeds from issuance of stock	0	47,219
Dividend payment to noncontrolling interest	0	(200)
Other financing activities	(551)	(881)
Net cash (used in) provided by financing activities	(1,957)	6,439
Effect of change in foreign currency exchange rates on cash, cash equivalents and restricted cash	(102)	264
Net decrease in cash, cash equivalents and restricted cash	(3,988)	(7,707)
Cash, cash equivalents and restricted cash at beginning of period	33,854	52,419
Cash, cash equivalents and restricted cash at end of period	$ 29,866	$ 44,712