Goodwill and Intangible Assets - Intangible Assets Other than Goodwill (Detail) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Indefinite-lived Intangible Assets [Line Items]
Not amortized intangible assets, Carrying Amount	$ 1,808	$ 1,772
Finite-Lived Intangible Assets [Line Items]
Amortized intangible assets, Gross Carrying Amount	28,820	24,253
Accumulated Amortization	(13,672)	(7,202)
Total	15,148	17,051
Intangible assets, Gross Carrying Amount	30,628	26,025
Intangible assets, Net Carrying Amount	16,956	18,823
TASER trademark
Indefinite-lived Intangible Assets [Line Items]
Not amortized intangible assets, Carrying Amount	900	900
Patents and trademarks pending
Indefinite-lived Intangible Assets [Line Items]
Not amortized intangible assets, Carrying Amount	908	872
Domain names
Finite-Lived Intangible Assets [Line Items]
Amortized intangible assets, Gross Carrying Amount	3,161	3,161
Accumulated Amortization	(656)	(428)
Total	$ 2,505	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	$ 2,916	2,697
Accumulated Amortization	(1,054)	(913)
Total	$ 1,862	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	$ 1,052	860
Accumulated Amortization	(567)	(397)
Total	$ 485	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	$ 3,724	1,377
Accumulated Amortization	(755)	(451)
Total	$ 2,969	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	$ 545	556
Accumulated Amortization	(423)	(346)
Total	$ 122	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	13,469
Accumulated Amortization	(8,573)	(3,956)
Total	$ 6,876	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	$ 1,973	2,133
Accumulated Amortization	(1,644)	(711)
Total	$ 329	$ 1,422