Business Acquisitions - Breon Enterprises Narrative (Details) - USD ($) $ in Thousands	Jul. 01, 2017	Dec. 31, 2017	Dec. 31, 2016
Business Acquisition [Line Items]
Goodwill		$ 14,927	$ 10,442
Breon Enterprises
Business Acquisition [Line Items]
Total purchase price	$ 4,200
Increase (decrease) in accounts receivable	2,200
Goodwill	$ 1,650
Intangible assets, weighted average useful life	2 years 1 month 6 days
TASER Weapons
Business Acquisition [Line Items]
Goodwill		1,453	562
TASER Weapons | Breon Enterprises
Business Acquisition [Line Items]
Goodwill	$ 800
Software and Sensors
Business Acquisition [Line Items]
Goodwill		$ 13,474	$ 9,880
Software and Sensors | Breon Enterprises
Business Acquisition [Line Items]
Goodwill	$ 800