Related Party Transactions - Additional Information (Detail) $ in Thousands		12 Months Ended
	Jul. 16, 2015 USD ($) contract	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Director
Related Party Transaction [Line Items]
Transaction expenses incurred by parent company		$ 200	$ 200	$ 200
Outstanding payables due to related party		31	8
Affiliate
Related Party Transaction [Line Items]
Annual software licensing fee	$ 45	80
Deferred costs related to annual subscription		$ 36	$ 20
Average remaining contractual term of leases	11 years 3 months 16 days
Employee | Tactical Safety Responses Limited
Related Party Transaction [Line Items]
Number of contracts | contract	2