Goodwill and Intangible Assets - Intangible Assets Other than Goodwill (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Indefinite-lived Intangible Assets [Line Items]
Not amortized intangible assets, Carrying Amount	$ 1,737		$ 1,737		$ 1,772
Finite-Lived Intangible Assets [Line Items]
Amortization of Intangible Assets	1,700	$ 1,000	3,000	$ 1,900
Amortized intangible assets, Gross Carrying Amount	28,791		28,791		24,253
Accumulated Amortization	(10,086)		(10,086)		(7,202)
Total	18,705		18,705		17,051
Intangible assets, Gross Carrying Amount	30,528		30,528		26,025
Intangible assets, Net Carrying Amount	20,442		20,442		18,823
TASER trademark
Indefinite-lived Intangible Assets [Line Items]
Not amortized intangible assets, Carrying Amount	900		900		900
Patents and trademarks pending
Indefinite-lived Intangible Assets [Line Items]
Not amortized intangible assets, Carrying Amount	837		837		872
Domain names
Finite-Lived Intangible Assets [Line Items]
Amortized intangible assets, Gross Carrying Amount	3,161		3,161		3,161
Accumulated Amortization	(580)		(580)		(428)
Total	2,581		$ 2,581		2,733
Domain names | Minimum
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible asset, useful life			5 years
Domain names | Maximum
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible asset, useful life			10 years
Issued patents
Finite-Lived Intangible Assets [Line Items]
Amortized intangible assets, Gross Carrying Amount	2,858		$ 2,858		2,697
Accumulated Amortization	(1,004)		(1,004)		(913)
Total	1,854		$ 1,854		1,784
Issued patents | Minimum
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible asset, useful life			4 years
Issued patents | Maximum
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible asset, useful life			15 years
Issued trademarks
Finite-Lived Intangible Assets [Line Items]
Amortized intangible assets, Gross Carrying Amount	1,010		$ 1,010		860
Accumulated Amortization	(545)		(545)		(397)
Total	465		$ 465		463
Issued trademarks | Minimum
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible asset, useful life			3 years
Issued trademarks | Maximum
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible asset, useful life			11 years
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Amortized intangible assets, Gross Carrying Amount	3,742		$ 3,742		1,377
Accumulated Amortization	(616)		(616)		(451)
Total	3,126		$ 3,126		926
Customer relationships | Minimum
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible asset, useful life			4 years
Customer relationships | Maximum
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible asset, useful life			8 years
Non-compete agreements
Finite-Lived Intangible Assets [Line Items]
Amortized intangible assets, Gross Carrying Amount	548		$ 548		556
Accumulated Amortization	(398)		(398)		(346)
Total	150		$ 150		210
Non-compete agreements | Minimum
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible asset, useful life			3 years
Non-compete agreements | Maximum
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible asset, useful life			4 years
Developed technology
Finite-Lived Intangible Assets [Line Items]
Amortized intangible assets, Gross Carrying Amount	15,449		$ 15,449		13,469
Accumulated Amortization	(5,594)		(5,594)		(3,956)
Total	9,855		$ 9,855		9,513
Developed technology | Minimum
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible asset, useful life			3 years
Developed technology | Maximum
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible asset, useful life			7 years
Re-acquired distribution rights
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible asset, useful life			2 years
Amortized intangible assets, Gross Carrying Amount	2,023		$ 2,023		2,133
Accumulated Amortization	(1,349)		(1,349)		(711)
Total	$ 674		$ 674		$ 1,422