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Significant Concentrations - Summary of Revenue and Accounts Receivable (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016
Concentration Risk [Line Items]
Revenue	$ 19,469	$ 19,653	$ 18,848	$ 22,841	$ 26,797	$ 22,467	$ 22,738	$ 25,439	$ 80,811	$ 97,441
Accounts receivable	18,014				21,579				18,014	21,579
Honeywell International Inc and affiliated entities [Member] \| Customer Concentration Risk [Member]
Concentration Risk [Line Items]
Revenue									12,278	13,696
Honeywell International Inc and affiliated entities [Member] \| Credit Concentration Risk [Member]
Concentration Risk [Line Items]
Accounts receivable	$ 8,659				$ 7,075				$ 8,659	$ 7,075
Honeywell International Inc and affiliated entities [Member] \| Revenue [Member] \| Customer Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration risk, percentage									15.00%	14.00%
Honeywell International Inc and affiliated entities [Member] \| Accounts receivable [Member] \| Credit Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration risk, percentage									48.00%	33.00%