Segment Information - Summary of Revenues on Percentage Basis by Geographic Regions (Detail)	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Segment Reporting Information [Line Items]
Revenues on a percentage basis by geographic regions, based on the region	100.00%	100.00%	100.00%	100.00%
United States [Member]
Segment Reporting Information [Line Items]
Revenues on a percentage basis by geographic regions, based on the region	72.00%	65.00%	66.00%	63.00%
South America [Member]
Segment Reporting Information [Line Items]
Revenues on a percentage basis by geographic regions, based on the region	10.00%	10.00%	10.00%	11.00%
Japan [Member]
Segment Reporting Information [Line Items]
Revenues on a percentage basis by geographic regions, based on the region	2.00%	2.00%	2.00%	2.00%
Europe [Member]
Segment Reporting Information [Line Items]
Revenues on a percentage basis by geographic regions, based on the region	11.00%	16.00%	16.00%	18.00%
Other [Member]
Segment Reporting Information [Line Items]
Revenues on a percentage basis by geographic regions, based on the region	5.00%	7.00%	6.00%	6.00%