Net Loss Attributable to ORBCOMM Inc. Common Stockholders - Summary of Basic and Diluted Calculations of EPS (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Earnings Per Share [Abstract]
Net loss attributable to ORBCOMM Inc. common stockholders	$ (3,295)	$ (39,694)	$ (20,614)	$ (53,777)
Weighted average number of common shares outstanding:
Basic number of common shares outstanding	78,649	73,762	77,158	72,396
Diluted number of common shares outstanding	78,649	73,762	77,158	72,396
Earnings per share:
Basic	$ (0.04)	$ (0.54)	$ (0.27)	$ (0.74)
Diluted	$ (0.04)	$ (0.54)	$ (0.27)	$ (0.74)