Revenues - Summary of Deferred Revenue (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Jan. 01, 2018	Dec. 31, 2017
Disaggregation of Revenue [Line Items]
Current	$ 107,016	$ 71,264	$ 70,401
Long-Term	74,417	$ 56,130	54,881
Total	181,433		125,282
TASER
Disaggregation of Revenue [Line Items]
Current	22,152		16,665
Long-Term	32,445		30,020
Total	54,597		46,685
Software and Sensors
Disaggregation of Revenue [Line Items]
Current	84,864		53,736
Long-Term	41,972		24,861
Total	126,836		78,597
Warranty
Disaggregation of Revenue [Line Items]
Current	21,070		18,794
Long-Term	23,363		22,814
Total	44,433		41,608
Warranty | TASER
Disaggregation of Revenue [Line Items]
Current	12,797		12,501
Long-Term	16,847		18,619
Total	29,644		31,120
Warranty | Software and Sensors
Disaggregation of Revenue [Line Items]
Current	8,273		6,293
Long-Term	6,516		4,195
Total	14,789		10,488
Hardware
Disaggregation of Revenue [Line Items]
Current	30,233		21,120
Long-Term	40,283		26,182
Total	70,516		47,302
Hardware | TASER
Disaggregation of Revenue [Line Items]
Current	9,355		4,164
Long-Term	15,598		11,401
Total	24,953		15,565
Hardware | Software and Sensors
Disaggregation of Revenue [Line Items]
Current	20,878		16,956
Long-Term	24,685		14,781
Total	45,563		31,737
Software and Sensors Services | Software and Sensors
Disaggregation of Revenue [Line Items]
Current	55,713		30,487
Long-Term	10,771		5,885
Total	$ 66,484		$ 36,372