Segment Data - Summary of Operational Information Relative to the Company's Reportable Segments (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting Information [Line Items]
Net sales	$ 114,791	$ 104,836	$ 99,226	$ 101,215	$ 94,651	$ 90,262	$ 79,643	$ 79,242	$ 420,068	$ 343,798	$ 268,245
Cost of sales									161,485	136,710	97,709
Gross margin	$ 65,346	$ 65,633	$ 63,143	$ 64,461	$ 63,016	$ 49,765	$ 45,637	$ 48,670	258,583	207,088	170,536
Sales, general and administrative									156,886	138,692	108,076
Research and development									76,856	55,373	30,609
Income from operations									24,841	13,023	31,851
Purchase of property and equipment									11,139	10,419	4,957
Purchase of intangible assets									558	1,024	3,495
Depreciation and amortization									10,615	8,041	3,658
TASER
Segment Reporting Information [Line Items]
Net sales									253,115	234,512	202,644
Cost of sales									80,354	72,054	61,930
Gross margin									172,761	162,458	140,714
Sales, general and administrative									90,910	78,202	63,617
Research and development									17,012	8,377	5,887
Income from operations									64,839	75,879	71,210
Software and Sensors
Segment Reporting Information [Line Items]
Net sales									166,953	109,286	65,601
Cost of sales									81,131	64,656	35,779
Gross margin									85,822	44,630	29,822
Sales, general and administrative									65,976	60,490	44,459
Research and development									59,844	46,996	24,722
Income from operations									(39,998)	(62,856)	(39,359)
Product
Segment Reporting Information [Line Items]
Net sales									327,635	285,859	238,573
Cost of sales									139,337	117,997	91,536
Product | TASER
Segment Reporting Information [Line Items]
Net sales									253,115	234,512	202,644
Cost of sales									80,354	72,054	61,930
Product | Software and Sensors
Segment Reporting Information [Line Items]
Net sales									74,520	51,347	35,929
Cost of sales									58,983	45,943	29,606
Service
Segment Reporting Information [Line Items]
Net sales									92,433	57,939	29,672
Cost of sales									22,148	18,713	6,173
Service | TASER
Segment Reporting Information [Line Items]
Net sales									0	0	0
Cost of sales									0	0	0
Service | Software and Sensors
Segment Reporting Information [Line Items]
Net sales									92,433	57,939	29,672
Cost of sales									$ 22,148	$ 18,713	$ 6,173