Summary of Significant Accounting Policies (Detail) $ in Thousands		9 Months Ended	12 Months Ended
	Jul. 31, 2016 USD ($)	Sep. 30, 2016 USD ($) contract measurement unit	Dec. 31, 2015 USD ($) contract
Decrease in Restricted Cash	$ 1,000
Number of contracts in progress that were identified as a loss contract (in contracts) | contract		2	2
Loss on contract termination		$ 3	$ 3
Unbilled receivables, current		8,042	7,312
Billings in excess of cost, current		$ 1,168	$ 1,858
Number of units with APC technology (in units) | unit		1,000
Minimum
Contract term (in months)		8 months
Critical operational measurements (in measurements) | measurement		3
Maximum
Contract term (in months)		16 months
Critical operational measurements (in measurements) | measurement		4