Long-Term Payment Obligation - Additional Information (Detail) - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2012
Related Party Transaction [Line Items]
Interest accreted on long-term payment obligation	$ 32,000	$ 55,000	$ 113,000	$ 179,000
Secure Keyboards Ltd
Related Party Transaction [Line Items]
Percentage of ownership by a related party following acquisition			24.50%		30.00%
Secure Networks Ltd
Related Party Transaction [Line Items]
Percentage of ownership by a related party following acquisition					9.00%
Settlement Agreement | Maximum
Related Party Transaction [Line Items]
Installment payment, contractual payment year			2020