Summary of Company's Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
Segment Reporting Information [Line Items]
Revenue	$ 23,683	$ 14,195	$ 20,558	$ 15,285	$ 16,314	$ 17,678	$ 14,931	$ 13,137	$ 73,721	$ 62,060	$ 84,867
Income (loss) from operations	$ (18,178)	$ (13,774)	$ (11,060)	$ (11,311)	$ (14,816)	$ (12,015)	$ (13,987)	$ (14,692)	(54,323)	(55,510)	(52,555)
Depreciation, impairment, inventory obsolescence and stock-based compensation expenses									50,300	37,538	25,929
Interest income									653	376	427
Interest expense									39	26	229
Operating Segments | Seismic
Segment Reporting Information [Line Items]
Revenue									47,109	33,792	60,565
Income (loss) from operations									(46,902)	(47,690)	(42,732)
Depreciation, impairment, inventory obsolescence and stock-based compensation expenses									47,620	34,945	23,696
Interest income									311	161	280
Operating Segments | Non-seismic
Segment Reporting Information [Line Items]
Revenue									26,027	27,708	23,758
Income (loss) from operations									4,153	4,093	3,031
Depreciation, impairment, inventory obsolescence and stock-based compensation expenses									785	746	505
Interest income										3	7
Corporate
Segment Reporting Information [Line Items]
Revenue									585	560	544
Income (loss) from operations									(11,574)	(11,913)	(12,854)
Depreciation, impairment, inventory obsolescence and stock-based compensation expenses									1,895	1,847	1,728
Interest income									342	212	140
Interest expense									$ 39	$ 26	$ 229