Inventories - Additional Information (Detail) - USD ($)	3 Months Ended
	Jun. 30, 2017	Mar. 31, 2017	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2016
Inventory Net Items Net Of Reserve Alternative [Abstract]
Inventory reserve balance	$ 200,000				$ 0
Charges for excess and obsolete inventory	$ 0	$ 200,000	$ 0	$ 200,000