Summary of Fair Values of Assets Acquired and Liabilities Assumed at Acquisition (Detail) - USD ($)		9 Months Ended
	Nov. 01, 2018	Sep. 30, 2019	Sep. 30, 2018	Mar. 31, 2019	Jan. 02, 2019	Dec. 31, 2018	Feb. 14, 2018
Business Acquisition [Line Items]
Goodwill		$ 10,128,000				$ 9,286,000
Purchase price net of cash acquired		1,287,000	$ 1,384,000
3VR
Business Acquisition [Line Items]
Cash							$ 195,000
Accounts receivable							2,029,000
Inventory							257,000
Prepaid expenses and other current assets							169,000
Property and equipment							334,000
Finite-lived intangibles							6,300,000
Total identifiable assets acquired							9,284,000
Accounts payable							(1,590,000)
Accrued expenses and liabilities							(726,000)
Deferred revenue							(2,928,000)
Debt							(3,622,000)
Total liabilities assumed							(8,866,000)
Net identifiable assets acquired							418,000
Goodwill							5,456,000
Purchase price							5,874,000
3VR | Trademarks
Business Acquisition [Line Items]
Finite-lived intangibles							400,000
3VR | Customer Relationships
Business Acquisition [Line Items]
Finite-lived intangibles							2,900,000
3VR | Developed Technology
Business Acquisition [Line Items]
Finite-lived intangibles							$ 3,000,000
Thursby Software Systems
Business Acquisition [Line Items]
Cash	$ 3,485,000
Accounts receivable	526,000
Inventory	1,361,000
Prepaid expenses and other current assets	12,000
Finite-lived intangibles	2,400,000
Total identifiable assets acquired	7,784,000
Accounts payable	(31,000)
Accrued expenses and liabilities	(67,000)
Deferred revenue	(243,000)
Other current liabilities	(4,307,000)
Total liabilities assumed	(4,648,000)
Net identifiable assets acquired	3,136,000
Goodwill	3,490,000
Purchase price	6,626,000
Less: cash acquired	(3,485,000)
Purchase price net of cash acquired	3,141,000
Thursby Software Systems | Trademarks
Business Acquisition [Line Items]
Finite-lived intangibles	200,000
Thursby Software Systems | Customer Relationships
Business Acquisition [Line Items]
Finite-lived intangibles	1,500,000
Thursby Software Systems | Developed Technology
Business Acquisition [Line Items]
Finite-lived intangibles	$ 700,000
Viscount Systems, Inc.
Business Acquisition [Line Items]
Accounts receivable					$ 636,000
Inventory					276,000
Prepaid expenses and other current assets					29,000
Property and equipment					190,000
Operating lease ROU assets					550,000
Finite-lived intangibles					1,670,000
Total identifiable assets acquired					3,351,000
Accounts payable					(372,000)
Operating lease liabilities					(61,000)
Accrued expenses and liabilities					(120,000)
Deferred revenue					(34,000)
Earnout consideration liability		$ (375,000)		$ (200,000)	(200,000)
Other current liabilities					(326,000)
Long-term operating lease liabilities					(489,000)
Total liabilities assumed					(1,602,000)
Net identifiable assets acquired					1,749,000
Goodwill					1,173,000
Purchase price					2,922,000
Viscount Systems, Inc. | Trademarks
Business Acquisition [Line Items]
Finite-lived intangibles					160,000
Viscount Systems, Inc. | Customer Relationships
Business Acquisition [Line Items]
Finite-lived intangibles					710,000
Viscount Systems, Inc. | Developed Technology
Business Acquisition [Line Items]
Finite-lived intangibles					$ 800,000