Goodwill and Intangible Assets - Intangible Assets Other than Goodwill (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Acquired Indefinite-lived Intangible Assets [Line Items]
Amortized, Gross Carrying Amount	$ 26,727	$ 24,253
Accumulated Amortization	(12,650)	(7,202)
Total	14,077	17,051
Not amortized, Gross Carrying Amount	1,858	1,772
Intangible assets, Gross Carrying Amount	28,585	26,025
Intangible Assets, Net Carrying Amount	15,935	18,823
Amortization of intangible assets	5,700	4,700	$ 900
TASER trademark
Acquired Indefinite-lived Intangible Assets [Line Items]
Not amortized, Gross Carrying Amount	900	900
Patents and trademarks pending
Acquired Indefinite-lived Intangible Assets [Line Items]
Not amortized, Gross Carrying Amount	958	872
Domain names
Acquired Indefinite-lived Intangible Assets [Line Items]
Amortized, Gross Carrying Amount	3,161	3,161
Accumulated Amortization	(732)	(428)
Total	$ 2,429	2,733
Domain names | Minimum
Acquired Indefinite-lived Intangible Assets [Line Items]
Useful Life	5 years
Domain names | Maximum
Acquired Indefinite-lived Intangible Assets [Line Items]
Useful Life	10 years
Issued patents
Acquired Indefinite-lived Intangible Assets [Line Items]
Amortized, Gross Carrying Amount	$ 2,940	2,697
Accumulated Amortization	(1,106)	(913)
Total	$ 1,834	1,784
Issued patents | Minimum
Acquired Indefinite-lived Intangible Assets [Line Items]
Useful Life	4 years
Issued patents | Maximum
Acquired Indefinite-lived Intangible Assets [Line Items]
Useful Life	15 years
Issued trademarks
Acquired Indefinite-lived Intangible Assets [Line Items]
Amortized, Gross Carrying Amount	$ 1,053	860
Accumulated Amortization	(599)	(397)
Total	$ 454	463
Issued trademarks | Minimum
Acquired Indefinite-lived Intangible Assets [Line Items]
Useful Life	3 years
Issued trademarks | Maximum
Acquired Indefinite-lived Intangible Assets [Line Items]
Useful Life	11 years
Customer relationships
Acquired Indefinite-lived Intangible Assets [Line Items]
Amortized, Gross Carrying Amount	$ 3,701	1,377
Accumulated Amortization	(880)	(451)
Total	$ 2,821	926
Customer relationships | Minimum
Acquired Indefinite-lived Intangible Assets [Line Items]
Useful Life	4 years
Customer relationships | Maximum
Acquired Indefinite-lived Intangible Assets [Line Items]
Useful Life	8 years
Non-compete agreements
Acquired Indefinite-lived Intangible Assets [Line Items]
Amortized, Gross Carrying Amount	$ 540	556
Accumulated Amortization	(439)	(346)
Total	$ 101	210
Non-compete agreements | Minimum
Acquired Indefinite-lived Intangible Assets [Line Items]
Useful Life	3 years
Non-compete agreements | Maximum
Acquired Indefinite-lived Intangible Assets [Line Items]
Useful Life	4 years
Developed technology
Acquired Indefinite-lived Intangible Assets [Line Items]
Amortized, Gross Carrying Amount	$ 13,404	13,469
Accumulated Amortization	(7,081)	(3,956)
Total	$ 6,323	9,513
Developed technology | Minimum
Acquired Indefinite-lived Intangible Assets [Line Items]
Useful Life	3 years
Developed technology | Maximum
Acquired Indefinite-lived Intangible Assets [Line Items]
Useful Life	7 years
Re-acquired distribution rights
Acquired Indefinite-lived Intangible Assets [Line Items]
Useful Life	2 years
Amortized, Gross Carrying Amount	$ 1,928	2,133
Accumulated Amortization	(1,813)	(711)
Total	$ 115	$ 1,422