Axon Enterprise (AXON) 10-Q 6 Nov 20 2020 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2020	Oct. 30, 2020
Document and Entity Information
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2020
Document Transition Report	false
Entity File Number	001-16391
Entity Registrant Name	Axon Enterprise, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	86-0741227
Entity Address, Address Line One	17800 North 85th Street
Entity Address, City or Town	Scottsdale
Entity Address, State or Province	AZ
Entity Address, Postal Zip Code	85255
City Area Code	480
Local Phone Number	991-0797
Title of 12(b) Security	Common Stock, $0.00001 Par Value
Trading Symbol	AAXN
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		63,549,898
Entity Central Index Key	0001069183
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q3
Amendment Flag	false

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 176,000	$ 172,250
Short-term investments	330,914	178,534
Accounts and notes receivable, net of allowance of $1,787 and $1,567 as of September 30, 2020 and December 31, 2019, respectively	172,803	146,878
Contract assets, net	63,105	38,102
Inventory	97,610	38,845
Prepaid expenses and other current assets	35,421	34,866
Total current assets	875,853	609,475
Property and equipment, net	102,718	43,770
Deferred tax assets, net	39,773	27,688
Intangible assets, net	10,260	12,771
Goodwill	25,012	25,013
Long-term investments	120,615	45,499
Long-term notes receivable, net of current portion	22,611	31,598
Long-term contract assets, net	15,019	9,644
Other assets	67,288	40,181
Total assets	1,279,149	845,639
Current liabilities:
Accounts payable	22,441	25,874
Accrued liabilities	74,114	45,001
Current portion of deferred revenue	154,731	117,864
Other current liabilities	5,137	3,853
Total current liabilities	258,555	195,566
Deferred revenue, net of current portion	87,733	87,936
Liability for unrecognized tax benefits	4,406	3,832
Long-term deferred compensation	4,150	3,936
Deferred tax liability, net	560	354
Other long-term liabilities	28,592	10,520
Total liabilities	383,996	302,144
Commitments and contingencies (Note 13)
Stockholders' equity:
Preferred stock, $0.00001 par value; 25,000,000 shares authorized; no shares issued and outstanding as of September 30, 2020 and December 31, 2019, respectively
Common stock, $0.00001 par value; 200,000,000 shares authorized; 63,548,081 and 59,497,759 shares issued and outstanding as of September 30, 2020 and December 31, 2019, respectively	1	1
Additional paid-in capital	908,584	528,272
Treasury stock at cost, 20,220,227 shares as of September 30, 2020 and December 31, 2019	(155,947)	(155,947)
Retained earnings	144,067	172,265
Accumulated other comprehensive loss	(1,552)	(1,096)
Total stockholders' equity	895,153	543,495
Total liabilities and stockholders' equity	1,279,149	845,639
Current portion of deferred revenue
Current liabilities:
Current portion of deferred revenue	154,731	117,864
Customer deposits
Current liabilities:
Current portion of deferred revenue	$ 2,132	$ 2,974

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Allowance on accounts and notes receivable	$ 1,787	$ 1,567
Preferred stock, par value (in dollars per share)	$ 0.00001	$ 0.00001
Preferred stock, shares authorized (in shares)	25,000,000	25,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.00001	$ 0.00001
Common stock, shares authorized (in shares)	200,000,000	200,000,000
Common stock, shares issued (in shares)	63,548,081	59,497,759
Common stock, shares outstanding (in shares)	63,548,081	59,497,759
Treasury stock, shares (in shares)	20,220,227	20,220,227

Unaudited Condensed Consolidate

Unaudited Condensed Consolidated Statements of Operations and Comprehensive Income (Loss) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Net sales	$ 166,442	$ 130,837	$ 454,863	$ 359,009
Cost of sales	68,202	50,668	179,838	144,363
Gross margin	98,240	80,169	275,025	214,646
Operating expenses:
Sales, general and administrative	74,443	48,424	209,763	134,678
Research and development	29,246	25,129	85,187	71,976
Total operating expenses	103,689	73,553	294,950	206,654
Income (loss) from operations	(5,449)	6,616	(19,925)	7,992
Interest and other income, net	2,040	1,820	4,594	5,978
Income (loss) before provision for income taxes	(3,409)	8,436	(15,331)	13,970
Provision for (benefit from) income taxes	(2,536)	2,332	12,227	709
Net income (loss)	$ (873)	$ 6,104	$ (27,558)	$ 13,261
Net income (loss) per common and common equivalent shares:
Basic (in dollars per share)	$ (0.01)	$ 0.10	$ (0.45)	$ 0.22
Diluted (in dollars per share)	$ (0.01)	$ 0.10	$ (0.45)	$ 0.22
Weighted average number of common and common equivalent shares outstanding:
Basic (in shares)	63,496	59,278	61,159	59,128
Diluted (in shares)	63,496	60,059	61,159	59,938
UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS)
Net income (loss)	$ (873)	$ 6,104	$ (27,558)	$ 13,261
Foreign currency translation adjustments	1,238	(227)	(456)	(285)
Comprehensive income (loss)	365	5,877	(28,014)	12,976
Product
Net sales	120,091	96,497	326,134	264,977
Cost of sales	57,798	42,445	150,507	120,265
Service
Net sales	46,351	34,340	128,729	94,032
Cost of sales	$ 10,404	$ 8,223	$ 29,331	$ 24,098

Unaudited Condensed Consolida_2

Unaudited Condensed Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Cumulative Effect, Period of Adoption, AdjustmentRetained Earnings	Cumulative Effect, Period of Adoption, Adjustment	Common Stock	Additional Paid-in Capital	Treasury Stock	Retained Earnings	Accumulated Other Comprehensive Loss	Total
Beginning balance (in shares) at Dec. 31, 2018			58,810,637		20,220,227
Beginning balance at Dec. 31, 2018			$ 1	$ 453,400	$ (155,947)	$ 171,383	$ (1,513)	$ 467,324
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock under employee plans, net (in shares)			298,649
Issuance of common stock under employee plans, net				(1,159)				(1,159)
Stock-based compensation				7,905				7,905
Net income (loss)						6,419		6,419
Foreign currency translation adjustments							50	50
Ending balance (in shares) at Mar. 31, 2019			59,109,286		20,220,227
Ending balance at Mar. 31, 2019			$ 1	460,146	$ (155,947)	177,802	(1,463)	480,539
Beginning balance (in shares) at Dec. 31, 2018			58,810,637		20,220,227
Beginning balance at Dec. 31, 2018			$ 1	453,400	$ (155,947)	171,383	(1,513)	467,324
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)								13,261
Foreign currency translation adjustments								(285)
Ending balance (in shares) at Sep. 30, 2019			59,320,793		20,220,227
Ending balance at Sep. 30, 2019			$ 1	480,747	$ (155,947)	184,644	(1,798)	507,647
Beginning balance (in shares) at Mar. 31, 2019			59,109,286		20,220,227
Beginning balance at Mar. 31, 2019			$ 1	460,146	$ (155,947)	177,802	(1,463)	480,539
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock under employee plans, net (in shares)			71,832
Issuance of common stock under employee plans, net				(869)				(869)
Stock-based compensation				8,627				8,627
Issuance of common stock for business combination (in shares)			70,613
Net income (loss)						738		738
Foreign currency translation adjustments							(108)	(108)
Ending balance (in shares) at Jun. 30, 2019			59,251,731		20,220,227
Ending balance at Jun. 30, 2019			$ 1	467,904	$ (155,947)	178,540	(1,571)	488,927
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock under employee plans, net (in shares)			69,062
Issuance of common stock under employee plans, net				(1,134)				(1,134)
Stock-based compensation				13,977				13,977
Net income (loss)						6,104		6,104
Foreign currency translation adjustments							(227)	(227)
Ending balance (in shares) at Sep. 30, 2019			59,320,793		20,220,227
Ending balance at Sep. 30, 2019			$ 1	480,747	$ (155,947)	184,644	(1,798)	507,647
Beginning balance (in shares) at Dec. 31, 2019			59,497,759		20,220,227
Beginning balance at Dec. 31, 2019	$ (640)	$ (640)	$ 1	528,272	$ (155,947)	172,265	(1,096)	543,495
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock under employee plans, net (in shares)			315,404
Issuance of common stock under employee plans, net				(5,162)				(5,162)
Stock-based compensation				20,195				20,195
Net income (loss)						4,074		4,074
Foreign currency translation adjustments							(2,372)	(2,372)
Ending balance (in shares) at Mar. 31, 2020			59,813,163		20,220,227
Ending balance at Mar. 31, 2020			$ 1	543,305	$ (155,947)	175,699	(3,468)	559,590
Beginning balance (in shares) at Dec. 31, 2019			59,497,759		20,220,227
Beginning balance at Dec. 31, 2019	$ (640)	$ (640)	$ 1	528,272	$ (155,947)	172,265	(1,096)	543,495
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)								(27,558)
Foreign currency translation adjustments								(456)
Ending balance (in shares) at Sep. 30, 2020			63,548,081		20,220,227
Ending balance at Sep. 30, 2020			$ 1	908,584	$ (155,947)	144,067	(1,552)	895,153
Beginning balance (in shares) at Mar. 31, 2020			59,813,163		20,220,227
Beginning balance at Mar. 31, 2020			$ 1	543,305	$ (155,947)	175,699	(3,468)	559,590
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock (in shares)			3,450,000
Issuance of common stock				306,779				306,779
Issuance of common stock under employee plans, net (in shares)			134,571
Issuance of common stock under employee plans, net				(310)				(310)
Stock-based compensation				33,835				33,835
Issuance of common stock for business combination (in shares)			70,613
Issuance of common stock for business combination								0
Net income (loss)						(30,759)		(30,759)
Foreign currency translation adjustments							678	678
Ending balance (in shares) at Jun. 30, 2020			63,468,347		20,220,227
Ending balance at Jun. 30, 2020			$ 1	883,609	$ (155,947)	144,940	(2,790)	869,813
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock under employee plans, net (in shares)			79,734
Issuance of common stock under employee plans, net				(1,119)				(1,119)
Stock-based compensation				26,094				26,094
Net income (loss)						(873)		(873)
Foreign currency translation adjustments							1,238	1,238
Ending balance (in shares) at Sep. 30, 2020			63,548,081		20,220,227
Ending balance at Sep. 30, 2020			$ 1	$ 908,584	$ (155,947)	$ 144,067	$ (1,552)	$ 895,153

Unaudited Condensed Consolida_3

Unaudited Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Cash flows from operating activities:
Net income (loss)	$ (27,558)	$ 13,261
Adjustments to reconcile net income to net cash used in operating activities:
Depreciation and amortization	8,944	8,196
Loss on disposal and abandonment of intangible assets	252	51
Loss on disposal and impairment of property and equipment, net	1,429	2,408
Stock-based compensation	80,124	30,195
Deferred income taxes	(11,670)	(3,946)
Unrecognized tax benefits	573	594
Other noncash, net	4,573	2,923
Provision for expected credit losses	776	0
Change in assets and liabilities:
Accounts and notes receivable and contract assets	(48,551)	(30,497)
Inventory	(59,371)	(6,302)
Prepaid expenses and other assets	(4,822)	(11,967)
Accounts payable, accrued and other liabilities	25,365	(13,528)
Deferred revenue	34,099	28,476
Net cash provided by operating activities	4,163	19,864
Cash flows from investing activities:
Purchases of investments	(516,687)	(242,693)
Proceeds from call / maturity of investments	287,199	92,207
Purchases of property and equipment	(66,023)	(12,111)
Proceeds from disposal of property and equipment	94	0
Purchases of intangible assets	(177)	(328)
Investment in unconsolidated affiliate	(4,700)	0
Net cash used in investing activities	(300,294)	(162,925)
Cash flows from financing activities:
Net proceeds from equity offering	306,779	0
Proceeds from options exercised	295	106
Income and payroll tax payments for net-settled stock awards	(6,886)	(3,268)
Net cash provided by (used in) financing activities	300,188	(3,162)
Effect of exchange rate changes on cash and cash equivalents	(303)	(678)
Net increase (decrease) in cash and cash equivalents	3,754	(146,901)
Cash and cash equivalents and restricted cash, beginning of period	172,355	351,027
Cash and cash equivalents and restricted cash, end of period	176,109	204,126
Supplemental disclosures:
Cash and cash equivalents	176,000	202,551
Restricted cash (Note 1)	109	1,575
Total cash, cash equivalents and restricted cash shown in the statements of cash flows	176,109	204,126
Cash paid for income taxes, net of refunds	7,678	2,422
Non-cash transactions
Property and equipment purchases in accounts payable and accrued liabilities	1,734	1,047
Commission converted to stock-based award	$ 0	$ 314

Organization and Summary of Sig

Organization and Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Summary of Significant Accounting Policies	1. Organization and Summary of Significant Accounting Policies Axon Enterprise, Inc. (“Axon,” the “Company,” "we," or "us") is a market-leading provider of law enforcement technology solutions. Our core mission is to protect life. We fulfill that mission through developing hardware and software products that advance the long term objectives of a) obsoleting the bullet, b) reducing social conflict, and c) enabling a fair and effective justice system. Our headquarters in Scottsdale, Arizona houses our executive management, sales, marketing, certain engineering, manufacturing, and other administrative support functions. We also have a software engineering development center located in Seattle, Washington, and subsidiaries located in Australia, Canada, Finland, Hong Kong, Germany, India, Italy, the Netherlands, the United Kingdom, and Vietnam. The accompanying unaudited condensed consolidated financial statements include the accounts of Axon Enterprise, Inc. and our wholly owned subsidiaries. All material intercompany accounts, transactions, and profits have been eliminated. Basis of Presentation and Use of Estimates These unaudited condensed consolidated financial statements have been prepared pursuant to the rules and regulations of the SEC. Certain information related to our organization, significant accounting policies and footnote disclosures normally included in financial statements prepared in accordance with accounting principles generally accepted in the United States (“U.S. GAAP”) has been condensed or omitted. The accounting policies followed in the preparation of these unaudited condensed consolidated financial statements are consistent with those followed in our annual consolidated financial statements for the year ended December 31, 2019, as filed on Form 10-K, with the exception of our adoption of certain accounting pronouncements which we describe below. In the opinion of management, these unaudited condensed consolidated financial statements contain all material adjustments, consisting only of normal recurring adjustments, necessary to fairly state our financial position, results of operations and cash flows for the periods presented and the presentations and disclosures herein are adequate when read in conjunction with our Form 10-K for the year ended December 31, 2019. The results of operations for the three months and nine months ended September 30, 2020 and 2019 are not necessarily indicative of the results to be expected for the full year (or any other period). Significant estimates and assumptions in these unaudited condensed consolidated financial statements include: ● product warranty reserves, ● inventory valuation, ● revenue recognition, ● expected credit loss reserves, ● valuation of goodwill, intangible and long-lived assets, ● recognition, measurement and valuation of current and deferred income taxes, ● stock-based compensation, ● recognition and measurement of lease liabilities, ● recognition and measurement of contingencies and accrued litigation expense, and ● fair values of identified tangible and intangible assets acquired and liabilities assumed in business combinations. Actual results could differ materially from those estimates. Segment Information Our operations are comprised of two reportable segments: the manufacture and sale of conducted electrical devices ("CEDs"), batteries, accessories, extended warranties and other products and services (the “TASER” segment); and the development, manufacture, and sale of software and sensors, which includes the sale of devices, wearables, applications, cloud and mobile products, and services (collectively, the “Software and Sensors” segment). In both segments, we report sales of products and services. Service revenue in both segments includes sales related to Axon Evidence. In the Software and Sensors segment, service revenue also includes other recurring cloud-hosted software revenue and related professional services. Collectively, this revenue is sometimes referred to as "Axon Cloud revenue." Reportable segments are determined based on discrete financial information reviewed by our Chief Executive Officer who is our chief operating decision maker ("CODM"). We organize and review operations based on products and services, and currently there are no operating segments that are aggregated. We perform an analysis of our reportable segments at least annually. Additional information related to our business segments is summarized in Note 15. Geographic Information and Major Customers / Suppliers For the three and nine months ended September 30, 2020 and 2019, no individual country outside the U.S. represented more than 10% of total net sales. Individual sales transactions in the international market are generally larger and occur more intermittently than in the domestic market due to the profile of our customers. For the three and nine months ended September 30, 2020 and 2019, no customer represented more than 10% of total net sales. At September 30, 2020 and December 31, 2019, no customer represented more than 10% of the aggregate balance of accounts and notes receivable and contract assets. We currently purchase both off the shelf and custom components, including, but not limited to, finished circuit boards, injection-molded plastic components, small machined parts, custom cartridge components, electronic components, and off the shelf sub-assemblies from suppliers located in the U.S., Australia, Canada, China, Germany, Japan, Mexico, and Taiwan. Although we currently obtain many of these components from single source suppliers, we own the injection molded component tooling, most of the designs, and the test fixtures used in their production for all custom components. As a result, we believe we could obtain alternative suppliers in most cases without incurring significant production delays. We also strategically hold safety stock levels on custom components to further reduce this risk. For off the shelf components, we believe that in most cases there are readily available alternative suppliers who can consistently meet our needs for these components. We acquire most of our components on a purchase order basis and do not have any significant long-term contracts with component suppliers. Income per Common Share Basic income per common share is computed by dividing net income by the weighted average number of common shares outstanding during the periods presented. Diluted income per share reflects the potential dilution from outstanding stock options and unvested restricted stock units. The calculation of the weighted average number of shares outstanding and earnings per share are as follows (in thousands except per share data): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, ​ Nine Months Ended September 30, ​ 2020 2019 2020 2019 Numerator for basic and diluted earnings per share: ​ ​ ​ ​ Net income (loss) ​ $ (873) ​ $ 6,104 ​ $ (27,558) ​ $ 13,261 Denominator: ​ ​ ​ ​ ​ Weighted average shares outstanding ​ 63,496 ​ 59,278 ​ 61,159 ​ 59,128 Dilutive effect of stock-based awards ​ — ​ 781 ​ — ​ 810 Diluted weighted average shares outstanding ​ 63,496 ​ 60,059 ​ 61,159 ​ 59,938 Anti-dilutive stock-based awards excluded ​ 12,793 ​ 12,477 ​ 12,904 ​ 12,546 Net income (loss) per common share: ​ ​ ​ ​ ​ Basic ​ $ (0.01) ​ $ 0.10 ​ $ (0.45) ​ $ 0.22 Diluted ​ $ (0.01) ​ $ 0.10 ​ $ (0.45) ​ $ 0.22 ​ Standard Warranties We warranty our CEDs, Axon cameras and certain related accessories from manufacturing defects on a limited basis for a period of one year after purchase and, thereafter, will repair or replace any defective unit for a fee. Estimated costs for the standard warranty are charged to cost of products sold when revenue is recorded for the related product. Future warranty costs are estimated based on historical data related to warranty claims and this rate is applied to current product sales. Historically, reserve amounts have been increased if management becomes aware of a component failure or other issue that could result in larger than anticipated warranty claims from customers. The warranty reserve is reviewed quarterly to verify that it sufficiently reflects the remaining warranty obligations based on the anticipated expenditures over the balance of the warranty obligation period, and adjustments are made when actual warranty claim experience differs from estimates. The warranty reserve is included in accrued liabilities on the accompanying condensed consolidated balance sheets. Changes in our estimated product warranty liabilities were as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Nine Months Ended September 30, ​ 2020 ​ 2019 Balance, beginning of period ​ $ 1,476 ​ $ 898 Utilization of reserve ​ (539) ​ (718) Warranty expense (benefit) ​ (192) ​ 891 Balance, end of period ​ $ 745 ​ $ 1,071 ​ Fair Value Measurements and Financial Instruments We use the fair value framework that prioritizes the inputs to valuation techniques for measuring financial assets and liabilities measured on a recurring basis and for non-financial assets and liabilities when these items are re-measured. Fair value is considered to be the exchange price in an orderly transaction between market participants, to sell an asset or transfer a liability at the measurement date. The hierarchy below lists three levels of fair value based on the extent to which inputs used in measuring fair value are observable in the market. We categorize each of our fair value measurements in one of these three levels based on the lowest level input that is significant to the fair value measurement in its entirety. These levels are: ● Level 1 – Valuation techniques in which all significant inputs are unadjusted quoted prices from active markets for assets or liabilities that are identical to the assets or liabilities being measured. ● Level 2 – Valuation techniques in which significant inputs include quoted prices from active markets for assets or liabilities that are similar to the assets or liabilities being measured and/or quoted prices for assets or liabilities that are identical or similar to the assets or liabilities being measured from markets that are not active. Also, model-derived valuations in which all significant inputs and significant value drivers are observable in active markets are Level 2 valuation techniques. ● Level 3 – Valuation techniques in which one or more significant inputs or significant value drivers are unobservable. Unobservable inputs are valuation technique inputs that reflect our own assumptions about inputs that market participants would use in pricing an asset or liability. We have cash equivalents and investments, which at September 30, 2020 and December 31, 2019 were comprised of money market funds, certificates of deposit, commercial paper, corporate bonds, municipal bonds, U.S. Government agency bonds, U.S. Treasury bills, U.S. Treasury inflation-protected securities, and U.S. Treasury repurchase agreements. See additional disclosure regarding the fair value of our cash equivalents and investments in Note 3. Included in the balance of other assets as of September 30, 2020 and December 31, 2019 was $4.2 million and $4.2 million, respectively, related to corporate-owned life insurance policies which are used to fund our deferred compensation plan. We determine the fair value of insurance contracts by obtaining the cash surrender value of the contracts from the issuer, a Level 2 valuation technique. In March 2020, we made an investment of $4.7 million in preferred stock and recorded preferred stock warrants at a fair value of $2.6 million, which is also included in the balance of other assets as of September 30, 2020. The estimated fair value of the investments was determined based on Level 3 inputs. As of September 30, 2020, management estimated that the fair value of the investment equaled its carrying value. ​ Our financial instruments also include accounts and notes receivable, accounts payable and accrued liabilities. Due to the short-term nature of these instruments, their fair values approximate their carrying values on the balance sheet. Restricted Cash Restricted cash balances as of September 30, 2020 and December 31, 2019 included $0.1 million primarily related to funds held in an international bank account for a country in which we are required to maintain a minimum balance to operate. Approximately half of the balance was included in prepaid expenses and other current assets on our condensed consolidated balance sheets, with the remainder included in other assets. Valuation of Goodwill, Intangibles and Long-lived Assets We evaluate whether events and circumstances have occurred that indicate the remaining estimated useful life of long-lived assets and identifiable intangible assets, excluding goodwill and intangible assets with indefinite useful lives, may warrant revision or that the remaining balance of these assets may not be recoverable. Such circumstances could include, but are not limited to, a change in the product mix, a change in the way products are created, produced or delivered, or a significant change in the way products are branded and marketed. In performing the review for recoverability, we estimate the future undiscounted cash flows expected to result from the use of the assets and their eventual disposition. The amount of the impairment loss, if impairment exists, is calculated based on the excess of the carrying amounts of the assets over their estimated fair value computed using discounted cash flows. We do not amortize goodwill and intangible assets with indefinite useful lives; rather such assets are required to be tested for impairment at least annually or sooner whenever events or changes in circumstances indicate that the assets may be impaired. We perform our annual goodwill and intangible asset impairment tests in the fourth quarter of each year. Recently Issued Accounting Guidance Recently Adopted Accounting Pronouncements In June 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments. ASU 2016-13 includes an impairment model (known as the current expected credit loss model) on financial instruments and other commitments that is based on expected losses rather than incurred losses. Under the new guidance, an entity recognizes as an allowance its estimate of expected credit losses, which the FASB believes will result in more timely recognition of such losses. The use of forecasted information is intended to incorporate more timely information in the estimate of expected credit loss. This ASU also requires enhanced disclosures relating to significant estimates and judgments used in estimating credit losses, as well as credit quality. Upon adoption, we recorded a noncash cumulative effect adjustment to retained earnings of $0.6 million, net of $0.2 million of income taxes, on the opening consolidated balance sheet as of January 1, 2020, reflecting an overall increase to the allowance for expected credit losses See Notes 3 and 4 for further disclosures related to Topic 326. ​ In August 2018, the FASB issued ASU 2018-13, Fair Value Measurement (Topic 820): Disclosure Framework—Changes to the Disclosure Requirements for Fair Value Measurement. ASU 2018-13 eliminates, adds and modifies certain disclosure requirements for fair value measurements. The amendments apply to the disclosures of changes in unrealized gains and losses, the range and weighted average of significant unobservable inputs used to develop Level 3 fair value measurements, and the narrative description of measurement uncertainty should be applied prospectively for only the most recent interim or annual period presented in the initial year of adoption. All other amendments should be applied retrospectively to all periods presented upon their effective date. Adoption of this ASU on January 1, 2020 did not have a material impact on our consolidated financial statements. ​ Effective the first quarter of 2021: ​ In December 2019, the FASB issued ASU 2019-12, Simplifying the Accounting for Income Taxes. The amendments in the ASU are effective for fiscal years beginning after December 15, 2020, including interim periods therein. Early adoption of the standard is permitted, including adoption in interim or annual periods for which financial statements have not yet been issued. Adoption of this ASU is not expected to have a material impact on our consolidated financial statements. ​ In January 2020, the FASB issued ASU No. 2020-01, Investments – Equity Securities (Topic 321), Investments – Equity Method and Joint Ventures (Topic 323), and Derivatives and Hedging (Topic 815) – Clarifying the Interactions Between Topic 321, Topic 323, and Topic 815 (a Consensus of the Emerging Issues Task Force). The guidance clarifies the interaction between ASU 2016-01, Financial Instruments – Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities and the ASU on equity method investments. ASU 2016-01 provides companies with an alternative to measure certain equity securities without a readily determinable fair value at cost, minus impairment, if any, unless an observable transaction for an identical or similar security occurs. ASU 2020-01 clarifies that for purposes of applying the Topic 321 measurement alternative, an entity should consider observable transactions that require it to either apply or discontinue the equity method of accounting under Topic 323, immediately before applying or upon discontinuing the equity method. In addition, the new ASU provides direction that a company should not consider whether the underlying securities would be accounted for under the equity method or the fair value option when it is determining the accounting for certain forward contracts and purchased options, upon either settlement or exercise. The amendments in this update become effective for fiscal years beginning after December 15, 2020, and interim periods within those fiscal years. Early adoption is permitted, and the amendments are to be applied prospectively. Adoption of this ASU is not expected to have a material impact on our consolidated financial statements. ​ Reclassification of Prior Year Presentation Certain prior year amounts, including the long-term portion of contract assets, have been reclassified for consistency with the current year presentation. These reclassifications are not material and had no effect on the reported results of operations.

Revenues

Revenues	9 Months Ended
	Sep. 30, 2020
Revenue from Contract with Customer [Abstract]
Revenues	2. Revenues Nature of Products and Services The following tables present our revenues by primary product and service offering (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, 2020 ​ Three Months Ended September 30, 2019 ​ ​ ​ Software and ​ ​ ​ ​ Software and ​ ​ ​ ​ TASER ​ Sensors ​ Total ​ TASER ​ Sensors ​ Total TASER 7 ​ $ 21,702 ​ $ — ​ $ 21,702 ​ $ 20,214 ​ $ — ​ $ 20,214 TASER X26P ​ 9,766 ​ — ​ 9,766 ​ 11,578 ​ — ​ 11,578 TASER X2 ​ 14,494 ​ — ​ 14,494 ​ 13,241 ​ — ​ 13,241 TASER Pulse ​ 2,981 ​ — ​ 2,981 ​ 1,132 ​ — ​ 1,132 Cartridges ​ 26,335 ​ — ​ 26,335 ​ 18,901 ​ — ​ 18,901 Axon Body ​ — ​ 15,978 ​ 15,978 ​ — ​ 6,763 ​ 6,763 Axon Flex ​ — ​ 1,589 ​ 1,589 ​ — ​ 1,670 ​ 1,670 Axon Fleet ​ — ​ 4,215 ​ 4,215 ​ — ​ 4,341 ​ 4,341 Axon Dock ​ — ​ 5,708 ​ 5,708 ​ — ​ 3,358 ​ 3,358 Axon Evidence and cloud services ​ 692 ​ 45,450 ​ 46,142 ​ 218 ​ 34,022 ​ 34,240 Extended warranties ​ 5,265 ​ 6,514 ​ 11,779 ​ 4,543 ​ 4,714 ​ 9,257 Other ​ 3,171 ​ 2,582 ​ 5,753 ​ 1,916 ​ 4,226 ​ 6,142 Total ​ $ 84,406 ​ $ 82,036 ​ $ 166,442 ​ $ 71,743 ​ $ 59,094 ​ $ 130,837 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Nine Months Ended September 30, 2020 ​ Nine Months Ended September 30, 2019 ​ ​ ​ Software and ​ ​ ​ ​ Software and ​ ​ ​ ​ TASER ​ Sensors ​ Total ​ TASER ​ Sensors ​ Total TASER 7 ​ $ 48,616 ​ $ — ​ $ 48,616 ​ $ 39,466 ​ $ — ​ $ 39,466 TASER X26P ​ 30,338 ​ — ​ 30,338 ​ 37,832 ​ — ​ 37,832 TASER X2 ​ 45,401 ​ — ​ 45,401 ​ 40,413 ​ — ​ 40,413 TASER Pulse ​ 6,374 ​ — ​ 6,374 ​ 2,920 ​ — ​ 2,920 Cartridges ​ 76,732 ​ — ​ 76,732 ​ 57,354 ​ — ​ 57,354 Axon Body ​ — ​ 40,645 ​ 40,645 ​ — ​ 18,820 ​ 18,820 Axon Flex ​ — ​ 3,452 ​ 3,452 ​ — ​ 4,517 ​ 4,517 Axon Fleet ​ — ​ 13,088 ​ 13,088 ​ — ​ 10,977 ​ 10,977 Axon Dock ​ — ​ 14,714 ​ 14,714 ​ — ​ 9,401 ​ 9,401 Axon Evidence and cloud services ​ 1,776 ​ 126,495 ​ 128,271 ​ 363 ​ 93,461 ​ 93,824 Extended warranties ​ 15,340 ​ 17,707 ​ 33,047 ​ 13,341 ​ 14,064 ​ 27,405 Other ​ 6,214 ​ 7,971 ​ 14,185 ​ 6,017 ​ 10,063 ​ 16,080 Total ​ $ 230,791 ​ $ 224,072 ​ $ 454,863 ​ $ 197,706 ​ $ 161,303 ​ $ 359,009 ​ ​ The following table presents our revenues disaggregated by geography (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, ​ ​ Nine Months Ended September 30, ​ ​ 2020 ​ ​ 2019 ​ ​ 2020 ​ 2019 United States $ 143,380 86 % ​ $ 110,809 85 % ​ $ 368,390 81 % $ 298,736 83 % Other countries ​ 23,062 14 ​ ​ 20,028 15 ​ ​ 86,473 19 ​ 60,273 17 ​ Total ​ $ 166,442 100 % ​ $ 130,837 100 % ​ $ 454,863 100 % $ 359,009 100 % ​ Contract Balances The following table presents our contract assets, contract liabilities and certain information related to these balances as of and for the nine months ended September 30, 2020 (in thousands): ​ ​ ​ ​ ​ ​ September 30, 2020 Contract assets, net ​ $ 78,124 Contract liabilities (deferred revenue) ​ 242,464 Revenue recognized in the period from: ​ Amounts included in contract liabilities at the beginning of the period ​ 113,422 ​ Contract liabilities (deferred revenue) consisted of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, 2020 ​ December 31, 2019 ​ Current Long-Term Total Current Long-Term Total Warranty: ​ ​ ​ ​ ​ ​ TASER ​ $ 13,267 ​ $ 14,824 ​ $ 28,091 ​ $ 12,716 ​ $ 16,378 ​ $ 29,094 Software and Sensors ​ 12,328 ​ 3,983 ​ 16,311 ​ 9,852 ​ 5,156 ​ 15,008 ​ ​ 25,595 ​ 18,807 ​ 44,402 ​ 22,568 ​ 21,534 ​ 44,102 Hardware: ​ ​ ​ ​ ​ ​ TASER ​ 15,621 ​ 12,124 ​ 27,745 ​ 9,569 ​ 15,468 ​ 25,037 Software and Sensors ​ 27,225 ​ 40,443 ​ 67,668 ​ 22,235 ​ 33,759 ​ 55,994 ​ ​ 42,846 ​ 52,567 ​ 95,413 ​ 31,804 ​ 49,227 ​ 81,031 Services: ​ ​ ​ ​ ​ ​ TASER ​ 722 ​ 1,091 ​ 1,813 ​ 293 ​ 765 ​ 1,058 Software and Sensors ​ 85,568 ​ 15,268 ​ 100,836 ​ 63,199 ​ 16,410 ​ 79,609 ​ ​ ​ 86,290 ​ ​ 16,359 ​ ​ 102,649 ​ ​ 63,492 ​ ​ 17,175 ​ ​ 80,667 Total ​ $ 154,731 ​ $ 87,733 ​ $ 242,464 ​ $ 117,864 ​ $ 87,936 ​ $ 205,800 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, 2020 ​ December 31, 2019 ​ Current Long-Term Total Current Long-Term Total TASER ​ $ 29,610 ​ $ 28,039 ​ $ 57,649 ​ $ 22,578 ​ $ 32,611 ​ $ 55,189 Software and Sensors ​ 125,121 ​ 59,694 ​ 184,815 ​ 95,286 ​ 55,325 ​ 150,611 Total ​ $ 154,731 ​ $ 87,733 ​ $ 242,464 ​ $ 117,864 ​ $ 87,936 ​ $ 205,800 ​ Remaining Performance Obligations As of September 30, 2020, we had approximately $1.51 billion of remaining performance obligations, which included both recognized contract liabilities as well as amounts that will be invoiced and recognized in future periods. The remaining performance obligations are limited only to arrangements that meet the definition of a contract under Topic 606 as of September 30, 2020. We expect to recognize between 20% - 25% of this balance over the next twelve months, and generally expect the remainder to be recognized over the following five

Cash, Cash Equivalents and Inve

Cash, Cash Equivalents and Investments	9 Months Ended
	Sep. 30, 2020
Cash and Cash Equivalents [Abstract]
Cash, Cash Equivalents and Investments	3. Cash, Cash Equivalents and Investments The following tables summarize our cash, cash equivalents, and held-to-maturity investments at September 30, 2020 and December 31, 2019 (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of September 30, 2020 ​ ​ ​ Gross Gross ​ ​ Cash and ​ ​ ​ ​ ​ ​ Amortized ​ Unrealized ​ Unrealized ​ ​ ​ ​ ​ Cash ​ Short-Term ​ Long-Term ​ ​ Cost ​ Gains ​ Losses ​ Fair Value ​ ​ Equivalents ​ Investments ​ Investments Cash ​ $ 91,499 ​ $ — ​ $ — ​ $ 91,499 ​ ​ $ 91,499 ​ $ — ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Level 1: ​ ​ ​ ​ ​ ​ ​ ​ Money market funds ​ 31,298 ​ — ​ — ​ 31,298 ​ ​ 31,298 ​ — ​ — Agency bonds ​ 68,111 ​ 141 ​ — ​ 68,252 ​ ​ — ​ 24,610 ​ 43,501 Treasury bills ​ ​ 57,284 ​ ​ 3 ​ ​ — ​ ​ 57,287 ​ ​ ​ 5,499 ​ ​ 51,785 ​ ​ — Subtotal ​ 156,693 ​ 144 ​ — ​ 156,837 ​ ​ 36,797 ​ 76,395 ​ 43,501 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Level 2: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ State and municipal obligations ​ 63,363 ​ ​ 49 ​ ​ (14) ​ ​ 63,398 ​ ​ ​ 1,001 ​ ​ 49,441 ​ ​ 12,921 Certificates of deposit ​ ​ 1,900 ​ ​ — ​ ​ — ​ ​ 1,900 ​ ​ ​ — ​ ​ 1,400 ​ ​ 500 Corporate bonds ​ ​ 222,817 ​ ​ 389 ​ ​ (166) ​ ​ 223,040 ​ ​ ​ 2,908 ​ ​ 156,178 ​ ​ 63,731 U.S. Treasury repurchase agreements ​ ​ 43,800 ​ ​ — ​ ​ — ​ ​ 43,800 ​ ​ ​ 43,800 ​ ​ — ​ ​ — Treasury inflation-protected securities ​ 3,270 ​ ​ 24 ​ ​ — ​ ​ 3,294 ​ ​ ​ — ​ ​ 3,270 ​ ​ — Commercial paper ​ 44,356 ​ ​ — ​ ​ — ​ ​ 44,356 ​ ​ ​ — ​ ​ 44,356 ​ ​ — Subtotal ​ 379,506 ​ ​ 462 ​ ​ (180) ​ ​ 379,788 ​ ​ ​ 47,709 ​ ​ 254,645 ​ ​ 77,152 Total ​ $ 627,698 ​ $ 606 ​ $ (180) ​ $ 628,124 ​ ​ $ 176,005 ​ $ 331,040 ​ $ 120,653 ​ We adopted Topic 326 on January 1, 2020, and applied the credit loss guidance related to held-to-maturity securities prospectively . Because we do not have any history of losses for our held-to-maturity investments, o ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, 2019 ​ ​ ​ Gross Gross ​ ​ Cash and ​ ​ ​ ​ ​ ​ Amortized ​ Unrealized ​ Unrealized ​ ​ ​ ​ ​ Cash ​ Short-Term ​ Long-Term ​ ​ Cost ​ Gains ​ Losses ​ Fair Value ​ ​ Equivalents ​ Investments ​ Investments Cash ​ $ 103,319 ​ $ — ​ $ — ​ $ 103,319 ​ ​ $ 103,319 ​ $ — ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Level 1: ​ ​ ​ ​ ​ ​ ​ ​ Money market funds ​ 8,845 ​ — ​ — ​ 8,845 ​ ​ 8,845 ​ — ​ — Agency bonds ​ 32,869 ​ 14 ​ (4) ​ 32,879 ​ ​ — ​ 15,131 ​ 17,738 Subtotal ​ 41,714 ​ 14 ​ (4) ​ 41,724 ​ ​ 8,845 ​ 15,131 ​ 17,738 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Level 2: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ State and municipal obligations ​ ​ 25,038 ​ ​ 8 ​ ​ — ​ ​ 25,046 ​ ​ ​ — ​ ​ 21,560 ​ ​ 3,478 Certificates of deposit ​ ​ 1,400 ​ ​ — ​ ​ — ​ ​ 1,400 ​ ​ ​ — ​ ​ 1,400 ​ ​ — Corporate bonds ​ ​ 135,175 ​ ​ 71 ​ ​ (30) ​ ​ 135,216 ​ ​ ​ 886 ​ ​ 113,241 ​ ​ 21,048 U.S. Treasury repurchase agreements ​ ​ 57,200 ​ ​ — ​ ​ — ​ ​ 57,200 ​ ​ ​ 57,200 ​ ​ — ​ ​ — Treasury inflation-protected securities ​ ​ 3,235 ​ ​ 14 ​ ​ — ​ ​ 3,249 ​ ​ ​ — ​ ​ — ​ ​ 3,235 Commercial paper ​ ​ 29,202 ​ ​ — ​ ​ — ​ ​ 29,202 ​ ​ ​ 2,000 ​ ​ 27,202 ​ ​ — Subtotal ​ ​ 251,250 ​ ​ 93 ​ ​ (30) ​ ​ 251,313 ​ ​ ​ 60,086 ​ ​ 163,403 ​ ​ 27,761 Total ​ $ 396,283 ​ $ 107 ​ $ (34) ​ $ 396,356 ​ ​ $ 172,250 ​ $ 178,534 ​ $ 45,499 ​

Expected Credit Losses

Expected Credit Losses	9 Months Ended
	Sep. 30, 2020
Expected Credit Losses
Expected Credit Losses	4. Expected Credit Losses We are exposed to credit losses primarily through sales of products and services. Our expected loss allowance methodology for accounts receivable, notes receivable, and contract assets is developed using historical collection experience, published or estimated credit default rates for entities that represent our customer base, current and future economic and market conditions and a review of the current status of customers' trade accounts receivables. Additionally, specific allowance amounts are established to record the appropriate provision for customers that have a higher probability of default. Our monitoring activities include account reconciliation, dispute resolution, payment confirmation, consideration of customers' financial condition and macroeconomic conditions. Balances are written off when determined to be uncollectible. ​ We considered the current and expected future economic and market conditions surrounding the COVID-19 pandemic and recorded additional credit loss expense of approximately $0.8 million during the nine months ended September 30, 2020. ​ We review receivables for U.S. and international customers separately to better reflect different published credit default rates and economic and market conditions. ​ The following table provides a roll-forward of the allowance for expected credit losses that is deducted from the amortized cost basis of accounts receivable, notes receivable, and contract assets to present the net amount expected to be collected (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Nine Months Ended September 30, 2020 ​ ​ ​ United States ​ ​ Other countries ​ ​ Total Balance, beginning of period ​ $ 1,395 ​ $ 172 ​ $ 1,567 Adoption of Topic 326, cumulative-effect adjustment to retained earnings ​ ​ 767 ​ ​ 1 ​ ​ 768 Provision for expected credit losses ​ ​ 578 ​ ​ 115 ​ ​ 693 Amounts written off charged against the allowance ​ ​ (61) ​ ​ (2) ​ ​ (63) Other, including dispositions and foreign currency translation ​ - ​ (3) ​ (3) Balance, end of period ​ $ 2,679 ​ $ 283 ​ $ 2,962 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, ​ 2020 Accounts receivable and notes receivable, current ​ $ 1,787 Contract assets, net ​ 711 Long-term notes receivable, net of current portion ​ 464 Total allowance for expected credit losses on customer receivables ​ $ 2,962 ​

Inventory

Inventory	9 Months Ended
	Sep. 30, 2020
Inventory Disclosure [Abstract]
Inventory	5. Inventory Inventories are stated at the lower of cost and net realizable value. Cost is determined using the weighted average cost of raw materials, which approximates the first-in, first-out (“FIFO”) method and includes allocations of manufacturing labor and overhead. Included in finished goods at September 30, 2020 and December 31, 2019 was $2.1 million and $1.4 million, respectively, of trial and evaluation hardware units. Provisions are made to reduce excess, obsolete or slow-moving inventories to their net realizable value. Inventory consisted of the following at September 30, 2020 and December 31, 2019 (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, 2020 December 31, 2019 Raw materials ​ $ 43,082 ​ $ 20,789 Finished goods ​ 54,528 ​ 18,056 Total inventory ​ $ 97,610 ​ $ 38,845 ​

Property and Equipment

Property and Equipment	9 Months Ended
	Sep. 30, 2020
Property, Plant and Equipment [Abstract]
Property and Equipment	6. Property and Equipment Property and equipment consisted of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Estimated ​ ​ ​ ​ ​ ​ ​ Useful Life September 30, 2020 December 31, 2019 Land ​ N/A ​ $ 57,052 ​ $ 2,900 Building and leasehold improvements ​ 3-39 years ​ ​ 20,330 ​ ​ 20,089 Production equipment ​ 3-7 years ​ 32,919 ​ 29,961 Computers, equipment and software ​ 3-5 years ​ 7,839 ​ 8,126 Furniture and office equipment ​ 5-7 years ​ 6,014 ​ 6,514 Vehicles ​ 5 years ​ 1,782 ​ 1,753 Website development costs ​ 3 years ​ 204 ​ 204 Capitalized internal-use software development costs ​ 3 years ​ 3,670 ​ 3,670 Construction-in-process ​ N/A ​ 17,546 ​ 12,385 Total cost ​ ​ ​ 147,356 ​ 85,602 Less: Accumulated depreciation ​ ​ ​ (44,638) ​ (41,832) Property and equipment, net ​ ​ $ 102,718 ​ $ 43,770 ​ In September 2020, we purchased a parcel of land located in Scottsdale, Arizona at auction from the Arizona State Land Department, on which we intend to construct our new manufacturing and office facility. The purchase price of the land was $49.1 million, plus selling fees, administrative fees, and certain other costs and expenses incurred by the Arizona State Land Department pursuant to the auction, for a total of approximately $50.6 million. We also capitalized legal and broker fees related to the purchase totaling approximately $1.3 million. Additionally, we capitalized approximately $2.2 million paid to the City of Scottsdale under a separate public infrastructure reimbursement development agreement; we are eligible for a refund of this and other infrastructure and development costs to be paid by Axon up to a total of approximately $9.4 million if certain milestones in the agreement are achieved. ​ ​ ​ ​ ​ ​ ​

Goodwill and Intangible Assets

Goodwill and Intangible Assets	9 Months Ended
	Sep. 30, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	7 The changes in the carrying amount of goodwill for the nine months ended September 30, 2020 were as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Software and ​ ​ ​ ​ TASER ​ Sensors ​ Total Balance, beginning of period ​ $ 1,354 ​ $ 23,659 ​ $ 25,013 Foreign currency translation adjustments ​ — ​ (1) ​ (1) Balance, end of period ​ $ 1,354 ​ $ 23,658 ​ $ 25,012 ​ Intangible assets (other than goodwill) consisted of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, 2020 ​ December 31, 2019 ​ ​ Gross ​ ​ Net Gross ​ ​ Net ​ ​ Useful ​ Carrying ​ Accumulated ​ Carrying ​ Carrying ​ Accumulated ​ Carrying ​ ​ Life ​ Amount ​ Amortization ​ Amount ​ Amount ​ Amortization ​ Amount Amortizable (definite-lived) intangible assets: ​ ​ ​ ​ ​ Domain names 5‑10 years ​ $ 3,161 ​ $ (1,263) ​ $ 1,898 ​ $ 3,161 ​ $ (1,035) ​ $ 2,126 Issued patents 5‑25 years ​ 3,216 ​ (1,510) ​ 1,706 ​ 3,271 ​ (1,339) ​ 1,932 Issued trademarks 3‑15 years ​ 1,200 ​ (573) ​ 627 ​ 1,166 ​ (678) ​ 488 Customer relationships 4‑8 years ​ 3,712 ​ (1,784) ​ 1,928 ​ 3,721 ​ (1,416) ​ 2,305 Non-compete agreements 3‑4 years ​ 452 ​ (419) ​ 33 ​ 450 ​ (404) ​ 46 Developed technology 3‑5 years ​ 10,660 ​ (8,167) ​ 2,493 ​ 10,660 ​ (6,528) ​ 4,132 Re-acquired distribution rights 2 years ​ 2,042 ​ (2,042) ​ — ​ 2,009 ​ (2,009) ​ — Total amortizable ​ 24,443 ​ (15,758) ​ 8,685 ​ 24,438 ​ (13,409) ​ 11,029 Non-amortizable (indefinite-lived) intangible assets: ​ ​ ​ ​ TASER trademark ​ 900 ​ ​ 900 ​ 900 ​ ​ 900 Patents and trademarks pending ​ 675 ​ ​ 675 ​ 842 ​ ​ 842 Total non-amortizable ​ 1,575 ​ ​ 1,575 ​ 1,742 ​ ​ 1,742 Total intangible assets ​ $ 26,018 ​ $ (15,758) ​ $ 10,260 ​ $ 26,180 ​ $ (13,409) ​ $ 12,771 ​ Amortization expense of intangible assets for the three and nine months ended September 30, 2020 was $0.8 million and $2.5 million, respectively. Amortization expense of intangible assets for the three and nine months ended September 30, 2019 was $0.8 million and $2.7 million, respectively. Estimated amortization for intangible assets with definite lives for the remaining three months of 2020, the next five years ended December 31, and thereafter, is as follows (in thousands): ​ ​ ​ ​ ​ 2020 remaining $ 831 2021 ​ 2,879 2022 ​ 1,277 2023 ​ 982 2024 ​ 899 2025 ​ 632 Thereafter ​ 1,185 Total ​ $ 8,685 ​

Other Long-Term Assets

Other Long-Term Assets	9 Months Ended
	Sep. 30, 2020
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Other Long-Term Assets	8. Other Long-Term Assets Other long-term assets consisted of the following at September 30, 2020 and December 31, 2019 (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, 2020 December 31, 2019 Cash surrender value of corporate-owned life insurance policies ​ $ 4,225 ​ $ 4,214 Deferred commissions (1) ​ 27,263 ​ 22,068 Restricted cash ​ 59 ​ 56 Operating lease assets ​ 22,368 ​ 9,653 Investment in unconsolidated affiliate (2)(4) ​ ​ 4,700 ​ ​ — Warrants for unconsolidated affiliate (3)(4) ​ ​ 2,588 ​ ​ — Prepaid expenses, deposits and other ​ 6,085 ​ 4,190 Total other long-term assets ​ $ 67,288 ​ $ 40,181 (1) Represents the incremental costs of obtaining contracts with customers, which consist primarily of sales commissions. These costs are ascribed to or allocated to the underlying performance obligations in the contracts and amortized consistent with the recognition timing of the revenue for the underlying performance obligations. (2) In March 2020, we made an investment in and entered into a commercial partnership agreement with Flock Group Inc., a provider of advanced security for neighborhoods and law enforcement. Our $4.7 million investment resulted in our ownership of approximately 5% of the outstanding equity interests of this company. We account for this investment under the ASC 321 measurement alternative for equity securities without readily determinable fair values, as there are no quoted market prices for the investment. The investment is measured at cost less impairment, adjusted for observable price changes and is assessed for impairment whenever events or changes in circumstances indicate that the carrying amount may not be recoverable. As of September 30, 2020, no impairment was recorded for the investment. (3) In conjunction with the equity investment in and commercial partnership with Flock Group Inc., we have the ability to commit additional capital over time through warrants where the exercisability and exercise prices are conditional on the achievement of certain partnership performance metrics. The fair value of the preferred stock warrants was estimated at $2.6 million using Monte Carlo simulation. ​ (4) In October 2020, we made an additional $2.1 million investment in Flock Group Inc. After this incremental investment, we hold approximately 4% of the outstanding equity interests. The issuance of new equity by Flock Group Inc. to us and other investors represents an observable price change for our existing investment and related warrants which will be reflected in the consolidated financial statements for the period ending December 31, 2020.

Accrued Liabilities

Accrued Liabilities	9 Months Ended
	Sep. 30, 2020
Payables and Accruals [Abstract]
Accrued Liabilities	9. Accrued Liabilities Accrued liabilities consisted of the following at September 30, 2020 and December 31, 2019 (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, 2020 December 31, 2019 Accrued salaries, benefits and bonus ​ $ 25,365 ​ $ 24,737 Accrued professional, consulting and lobbying fees ​ 11,483 ​ 3,235 Accrued warranty expense ​ 745 ​ 1,476 Accrued income and other taxes ​ 18,086 ​ 3,362 Accrued inventory in transit ​ ​ 10,185 ​ ​ 4,156 Other accrued expenses ​ 8,250 ​ 8,035 Accrued liabilities ​ $ 74,114 ​ $ 45,001 ​

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2020
Income Tax Disclosure [Abstract]
Income Taxes	10. Income Taxes We file income tax returns for federal purposes and in many states, as well as in multiple foreign jurisdictions. Our tax filings remain subject to examination by applicable tax authorities for a certain length of time, generally three to four years, following the tax year to which these filings relate. In July 2020, we received notification from the Internal Revenue Service that the audit of our U.S. federal income tax return for fiscal year 2016 was completed. During the second quarter we began an audit with the State of California for our fiscal year 2016 and 2017 state tax returns, which is currently ongoing. Additionally, we have been notified that an audit will commence for Axon Public Safety Southeast Asia LLC, our entity in Vietnam. The tax period has not yet been defined. On March 27, 2020, the U.S. federal government enacted the Coronavirus Aid, Relief, and Economic Security Act (the “CARES Act”). The CARES Act is an emergency economic stimulus package in response to the coronavirus outbreak which, among other things, contains numerous income tax provisions. Some of these tax provisions are expected to be effective retroactively for years ending before the date of enactment. We are continuing to evaluate the implications of the CARES Act, but its impact on our financial statements and related disclosures is not expected to be material. In April 2020, recent interpretations of a German law relating to withholding taxes on intellectual property rights emerged. We have evaluated this law and do not expect a material impact to our financial position or results of operations. The issuance of new equity in October 2020 by Flock Group Inc. to us and other investors represents an observable price change for our existing investment and related warrants which will be reflected in the consolidated financial statements for the period ending December 31, 2020. The taxability of any unrealized gain recognized will be deferred, creating a deferred tax liability in the period in which it is recognized. Deferred Tax Assets Net deferred income tax assets at September 30, 2020, primarily include R&D tax credits, stock-based compensation expense, deferred revenue, accruals and reserves, and net operating losses, partially offset by accelerated depreciation expense and valuation allowance reserve. Our total net deferred tax assets at September 30, 2020 were $39.2 million. In preparing our condensed consolidated financial statements, management assesses the likelihood that its deferred tax assets will be realized from future taxable income. In evaluating our ability to recover our deferred income tax assets, management considers all available positive and negative evidence, including our operating results, ongoing tax planning and forecasts of future taxable income on a jurisdiction by jurisdiction basis. A valuation allowance is established if it is determined that it is more likely than not that some portion or all of the net deferred tax assets will not be realized. Management exercises significant judgment in determining our provisions for income taxes, our deferred tax assets and liabilities, and our future taxable income for purposes of assessing our ability to utilize any future tax benefit from our deferred tax assets. As of September 30, 2020, we continue to demonstrate three-year cumulative pre-tax income in the U.S. federal and state tax jurisdictions; however, we have Arizona R&D Tax Credits expiring unutilized each year. Therefore, management has concluded that it is more likely than not that our Arizona R&D deferred tax asset will not be realized. We have certain foreign net operating loss carryovers, which have previously been fully offset with a valuation allowance. As of September 30, 2020, we now have cumulative pre-tax income in the U.K. and Canada, as measured over a three year rolling period, along with positive evidence from projections of future taxable income growth for both jurisdictions. Therefore, we have released the full valuation allowances against net operating loss carryovers in the U.K. and Canada of $1.3 million and $0.3 million, respectively, in the third quarter of 2020. In Australia, we have determined that sufficient deferred tax liabilities will reverse in order to realize all assets except one long-lived intangible where there is not an expectation that the asset may be realized. Therefore, we have recorded a partial valuation allowance for Australia. We complete R&D tax credit studies for each year that an R&D tax credit is claimed for federal, Arizona, and California income tax purposes. Management has made the determination that it is more likely than not that the full benefit of the R&D tax credit will not be sustained on examination and recorded a liability for unrecognized tax benefits of $7.0 million as of September 30, 2020. Should the unrecognized benefit of $7.0 million be recognized, our effective tax rate would be favorably impacted. Approximately $2.8 million of the unrecognized tax benefit associated with R&D credits has been netted against the R&D deferred tax asset. Effective Tax Rate Our overall effective tax rate for the nine months ended September 30, 2020, after discrete period adjustments, was (79.8%). Before discrete adjustments, the tax rate was (137.0%), which differs from the federal statutory rate, primarily due to the impact of the executive compensation limitation under Internal Revenue Code ("IRC") Section 162(m) on a projected pre-tax loss for the year. The effective tax rate was favorably impacted by a $6.6 million discrete tax benefit primarily associated with windfalls related to stock-based compensation for restricted stock units (“RSUs”) that vested or stock options that were exercised during the nine months ended September 30, 2020.

Stockholders' Equity

Stockholders' Equity	9 Months Ended
	Sep. 30, 2020
Equity [Abstract]
Stockholders' Equity	11. Stockholders’ Equity Follow-on offering ​ In June 2020, we sold 3,450,000 shares of our common stock, which included 450,000 shares pursuant to the full exercise of the underwriters' option to purchase additional shares, in an underwritten public offering at a price of $92.00 per share, which resulted in gross proceeds of $317.4 million. Net proceeds to us after deducting fees, commissions, and other expenses related to the offering were $306.8 million. ​ Performance-based stock awards We have issued performance-based stock options and performance-based RSUs, the vesting of which is generally contingent upon the achievement of certain performance criteria related to our operating performance, as well as successful and timely development and market acceptance of future product introductions. In addition, certain of the performance RSUs have additional service requirements subsequent to the achievement of the performance criteria. Compensation expense is recognized over the requisite service period, which is defined as the longest explicit, implicit or derived service period based on management’s estimate of the probability of the performance criteria being satisfied, adjusted at each balance sheet date. For both service-based and performance-based RSUs, we account for forfeitures as they occur as a reduction to stock-based compensation expense and additional paid-in-capital. For performance-based options with a vesting schedule based entirely on the attainment of both performance and market conditions, stock-based compensation expense is recognized for each pair of performance and market conditions over the longer of the expected achievement period of the performance and market conditions, beginning at the point in time that the relevant performance condition is considered probable of achievement. The fair value of such awards is estimated on the grant date using Monte Carlo simulations. CEO Performance Award On May 24, 2018, our stockholders approved the Board of Directors’ grant of 6,365,856 stock option awards to Patrick W. Smith, our CEO (the “CEO Performance Award”). The CEO Performance Award consists of 12 vesting tranches with a vesting schedule based entirely on the attainment of both operational goals (performance conditions) and market capitalization goals (market conditions), assuming continued employment either as the CEO or as both Executive Chairman and Chief Product Officer and service through each vesting date. Each of the 12 vesting tranches of the CEO Performance Award have a 10-year Award)") is defined as net income (loss) attributable to common stockholders before interest expense, investment interest income, provision (benefit) for income taxes, depreciation and amortization, and stock-based compensation expense. ​ ​ ​ ​ ​ Eight Separate Adjusted EBITDA (CEO Eight Separate Revenue Goals (1) ​ Performance Award) Goals (in thousands) ​ (in thousands) Goal #1, $710,058 Goal #9, $125,000 Goal #2, $860,058 Goal #10, $155,000 Goal #3, $1,010,058 Goal #11, $175,000 Goal #4, $1,210,058 Goal #12, $190,000 Goal #5, $1,410,058 Goal #13, $200,000 Goal #6, $1,610,058 Goal #14, $210,000 Goal #7, $1,810,058 Goal #15, $220,000 Goal #8, $2,010,058 Goal #16, $230,000 (1) In connection with the business acquisition that was completed during the three months ended June 30, 2018, the revenue goals were adjusted for the acquiree’s Target Revenue, as defined in the CEO Performance Award agreement. As of September 30, 2020, the following operational goals were considered probable of achievement: ● Total revenue of $710.1 million, $860.1 million, and $1,010.1 million; and ● Adjusted EBITDA (CEO Performance Award) of $125.0 million, $155.0 million, $175.0 million, $190.0 million, $200.0 million, $210.0 million, $220.0 million, and $230.0 million. The first three market capitalization goals have been achieved as of September 30, 2020, and the fourth market capitalization goal was achieved in October 2020. However, none of the stock options granted under the CEO Performance Award have vested thus far as the operational goals have not yet been achieved as of September 30, 2020. As there are eleven operational goals considered probable of achievement, we recorded stock-based compensation expense of $69.5 million related to the CEO Performance Award from the Grant Date through September 30, 2020. The number of stock options that would vest related to the eleven tranches is approximately 5.8 million shares. As of September 30, 2020, we had $158.9 million of total unrecognized stock-based compensation expense for the performance goals that were considered probable of achievement, which will be recognized over a weighted-average period of 5.09 years. As of September 30, 2020, we had unrecognized stock-based compensation expense of $17.6 million for the performance goals that were considered not probable of achievement. eXponential Stock Performance Plan On February 12, 2019, our shareholders approved the 2019 Stock Incentive Plan (the “2019 Plan”), which was adopted by the Board of Directors to reserve a sufficient number of shares to facilitate our eXponential Stock Performance Plan (“XSPP”) and grants of eXponential Stock Units (“XSUs”) under the plan. Initial awards under the plan were granted in January 2019, with additional employee awards granted since that date. During the three and nine months ended September 30, 2020, we granted an additional 0.1 million and 0.3 million XSUs, respectively. The XSUs are grants of RSUs, each with a term of approximately nine years, that vest in 12 equal tranches. Each of the 12 tranches will vest upon certification by the Compensation Committee of the Board of Directors that both (i) the market capitalization goal for such tranche, which begins at $2.5 billion for the first tranche and increases by increments of $1.0 billion thereafter, and (ii) any one of eight operational goals focused on revenue or eight operational goals focused on Adjusted EBITDA (CEO Performance Award) have been met for the previous four consecutive fiscal quarters. The XSPP contains an anti-dilution provision incorporated into the plan based on shareholder feedback, which affects the calculation of the market capitalization goals in the plan. The plan defines a maximum number of shares outstanding that may be used in the calculation of the market capitalization goals (the “XSU Maximum”). If the actual number of shares outstanding exceeds the XSU Maximum guardrail, then the lower pre-defined number of shares in the XSU Maximum, rather than the higher actual number of shares outstanding, is used to calculate market capitalization for the determination of the market capitalization goals in the XSPP, which, together with the operational goals, determines whether XSUs vest for participating employees. The XSU Maximum is defined as the actual number of shares outstanding on the original XSU grant date of January 2, 2019, increased by a 3% annual rate over the term of the XSPP and by shares issued upon the exercise of CEO Performance Award options. The XSU Maximum is also adjusted for acquisitions, spin-offs or other changes in the number of outstanding shares of common stock, if such changes have a corresponding adjustment on the market capitalization goals. New shares issued for any other reasons, including shares issued upon vesting of XSUs, RSUs, and PSUs as well as shares issued to raise capital through equity issuances or in other transactions, do not increase the XSU Maximum. The market capitalization and operational goals are identical to the CEO Performance Award, but a different number of shares is used to calculate the market capitalization goals if shares outstanding exceed the XSU Maximum. Additionally, because the grant date is different than that of the CEO Performance Award, the measurement period for market capitalization is not identical. As of September 30, 2020, actual shares outstanding exceeded the XSU Maximum as a result of the common stock offering completed in June 2020. Accordingly, market capitalization as calculated for the purposes of achieving additional goals uses the lower XSU Maximum share amount rather than actual shares outstanding. The first three market capitalization goals have been achieved as of September 30, 2020, and the fourth market capitalization goal was achieved in November 2020. However, none of the XSU tranches have vested thus far as the operational goals have not yet been achieved as of September 30, 2020. As there are eleven operational goals considered probable of achievement, we recorded stock-based compensation expense of $42.0 million related to the XSU awards from their respective grant dates through September 30, 2020. The number of XSU awards that would vest related to the eleven tranches is approximately 5.0 million shares. As of September 30, 2020, we had $139.9 million of total unrecognized stock-based compensation expense for the performance goals that were considered probable of achievement, which will be recognized over a weighted-average period of 4.91 years. As of September 30, 2020, we had unrecognized stock-based compensation expense of $11.4 million for the performance goals that were considered not probable of achievement. Restricted Stock Units The following table summarizes RSU activity for the nine months ended September 30, 2020 (number of units and aggregate intrinsic value in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Number of Weighted Average Aggregate ​ ​ Units ​ Grant-Date Fair Value ​ Intrinsic Value Units outstanding, beginning of year 1,249 ​ $ 45.47 ​ Granted 279 ​ 78.86 ​ Released (394) ​ 39.00 ​ Forfeited (85) ​ 50.82 ​ Units outstanding, end of period 1,049 ​ 56.34 ​ $ 95,112 ​ Aggregate intrinsic value represents our closing stock price on the last trading day of the period, which was $90.70 per share, multiplied by the number of RSUs outstanding. As of September 30, 2020, there was $41.7 million in unrecognized compensation costs related to RSUs under our stock plans for shares that are expected to vest. We expect to recognize the cost related to the RSUs over a weighted average period of 1.99 years. RSUs are released when vesting requirements are met. Certain RSUs that vested in the nine months ended September 30, 2020 were net-share settled such that we withheld shares to cover the employees’ tax obligation for the applicable income and other employment taxes, and remitted the cash to the appropriate taxing authorities. Total shares withheld related to RSUs were approximately 13 thousand and had a value of $1.1 million on their respective vesting dates as determined by the closing stock price on such dates. Payments for the employees’ tax obligations are reflected as a financing activity within the condensed consolidated statements of cash flows. We record a liability for the tax withholding to be paid by us as a reduction to additional paid-in capital. Performance Stock Units The following table summarizes Performance Stock Units (“PSUs”) activity, inclusive of XSUs, for the nine months ended September 30, 2020 (number of units and aggregate intrinsic value in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Number of Weighted Average Aggregate ​ ​ Units ​ Grant-Date Fair Value ​ Intrinsic Value Units outstanding, beginning of year 6,033 ​ $ 34.47 ​ Granted 380 ​ 55.94 ​ Released (160) ​ 25.20 ​ Forfeited (474) ​ 43.09 ​ Units outstanding, end of period 5,779 ​ 35.43 ​ $ 524,180 ​ Aggregate intrinsic value represents our closing stock price on the last trading day of the period, which was $90.70 per share, multiplied by the number of PSUs outstanding. As of September 30, 2020, there was $143.9 million in unrecognized compensation costs related to PSUs under our stock plans for shares that are expected to vest. We expect to recognize the cost related to the PSUs over a weighted average period of 4.82 years. PSUs are released when vesting requirements are met. As of September 30, 2020, the performance criteria had been met for approximately 0.1 million of the 5.8 million PSUs outstanding. Certain of the PSUs outstanding as of September 30, 2020 can vest with a range of shares earned being between 0% and 200% of the targeted shares granted, depending on the final achievement of pre-determined performance criteria as of the vesting date. The amount of PSUs included in the table above related to such grants is the target level. The maximum additional number of PSUs that could be earned is 0.2 million, which are not included in the table above. On November 3, 2020, the Compensation Committee of our Board of Directors approved a modification to the definition of a metric for certain of our outstanding PSU awards. We will account for this change as a Type III modification under ASC 718 since the expectation of the attainment for this metric changed from improbable to probable. We expect to recognize additional stock-based compensation of approximately $3.5 million over the remaining requisite service period, beginning from the modification date. Certain PSUs that vested in the nine months ended September 30, 2020 were net-share settled such that we withheld shares to cover the employees’ tax obligation for the applicable income and other employment taxes, and remitted the cash to the appropriate taxing authorities. Total shares withheld related to PSUs were less than one thousand and had a value of $0.1 million on their respective vesting dates as determined by the closing stock price on such dates. Payments for the employees’ tax obligations are reflected as a financing activity within the condensed consolidated statements of cash flows. We record a liability for the tax withholding to be paid by us as a reduction to additional paid-in capital. Stock Option Activity The following table summarizes stock option activity for the nine months ended September 30, 2020 (number of units and aggregate intrinsic value in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ ​ ​ ​ ​ Weighted ​ Average ​ ​ ​ ​ ​ Number ​ Average ​ Remaining ​ ​ ​ ​ ​ of ​ Exercise ​ Contractual ​ Aggregate ​ ​ Options ​ Price ​ Life (years) ​ Intrinsic Value Options outstanding, beginning of year 6,431 ​ $ 28.34 ​ Granted — ​ — ​ Exercised (65) ​ 4.52 ​ Expired / terminated — ​ — ​ Options outstanding, end of period 6,366 ​ 28.58 7.41 ​ $ 395,449 Options exercisable, end of period 1 ​ 4.70 0.26 ​ 2 ​ Aggregate intrinsic value represents the difference between the exercise price of the underlying stock option awards and the closing market price of our common stock of $90.70 on September 30, 2020. The intrinsic value of options exercised for the nine months ended September 30, 2020 and 2019 was $5.1 million and $1.1 million, respectively. As of September 30, 2020, total options outstanding included 6.4 million unvested performance-based stock options. Of this total, 5.8 million options relate to tranches of the CEO Performance Award considered probable of achievement and 0.5 million relate to the tranche of the CEO Performance Award not considered probable of achievement. Stock-based Compensation Expense The following table summarizes the composition of stock-based compensation expense for the three and nine months ended September 30, 2020 and 2019 (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, ​ Nine Months Ended September 30, ​ 2020 2019 2020 2019 Cost of products sold and services delivered ​ $ 744 ​ $ 312 ​ $ 2,170 ​ $ 775 Sales, general and administrative expenses ​ 19,117 ​ 9,508 ​ 60,853 ​ 19,130 Research and development expenses ​ 6,233 ​ 3,843 ​ 17,101 ​ 10,290 Total stock-based compensation expense ​ $ 26,094 ​ $ 13,663 ​ $ 80,124 ​ $ 30,195 ​ Stock Incentive Plan In February 2019, our shareholders approved the 2019 Plan authorizing an additional 6.0 million shares, plus remaining available shares under prior plans, for issuance under the new plan. Combined with the legacy stock incentive plans, there are 2.0 million shares available for grant as of September 30, 2020. Stock Repurchase Plan In February 2016, our Board of Directors authorized a stock repurchase program to acquire up to $50.0 million of our outstanding common stock subject to stock market conditions and corporate considerations. During the nine months ended September 30, 2020 and 2019, no common shares were purchased under the program. As of September 30, 2020, $16.3 million remains available under the plan for future purchases. Any future purchases will be discretionary.

Line of Credit

Line of Credit	9 Months Ended
	Sep. 30, 2020
Debt Disclosure [Abstract]
Line of Credit	12. Line of Credit We have a $50.0 million unsecured revolving line of credit with a domestic bank, of which $10.0 million is available for letters of credit. The credit agreement matures on December 31, 2021 and has an accordion feature which allows for an increase in the total line of credit up to $100.0 million, subject to certain conditions, including the availability of additional bank commitments. At September 30, 2020 and December 31, 2019, there were no borrowings under the line. Under the terms of the line of credit, available borrowings are reduced by outstanding letters of credit. As of September 30, 2020, we had letters of credit outstanding of approximately $6.1 million under the facility and available borrowing of $43.9 million, excluding amounts available under the accordion feature. Advances under the line of credit bear interest at LIBOR plus 1.0 to 1.5% per year determined in accordance with a pricing grid based on our funded debt to earnings before interest, taxes, depreciation and amortization ("EBITDA") ratio. We are required to comply with a maximum funded debt to EBITDA ratio of no greater than 2.50 to 1.00 based upon a trailing four fiscal quarter period. At September 30, 2020, our funded debt to EBITDA ratio was 0.00 to 1.00.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2020
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	13. Commitments and Contingencies Product Litigation As a manufacturer of weapons and other law enforcement tools used in high-risk field environments, we are often the subject of products liability litigation concerning the use of our products. We are currently named as a defendant in 12 lawsuits (two pending dismissal) in which the plaintiffs allege either wrongful death or personal injury in situations in which a TASER CED was used by law enforcement officers in connection with arrests or training. While the facts vary from case to case, these product liability claims typically allege defective product design, manufacturing, and/or failure to warn. They seek compensatory and sometimes punitive damages, often in unspecified amounts. We continue to aggressively defend all product litigation. As a general rule, it is our policy not to settle suspect injury or death cases. Exceptions are sometimes made where the settlement is strategically beneficial to us. Due to the confidential nature of our litigation strategy and the confidentiality agreements that are executed in the event of a settlement, we do not identify or comment on specific settlements by case or amount. Based on current information, we do not believe that the outcome of any such legal proceeding will have a material effect on our financial position, results of operations, or cash flows. We are self-insured for the first $5.0 million of any product claim made after 2014. No judgment or settlement has ever exceeded this amount in any products case. We continue to maintain product liability insurance coverage, including an insurance policy fronting arrangement, above our self-insured retention with various limits depending on the policy period. The litigation information in this note is current through the date of these financial statements. U.S. Federal Trade Commission Litigation The U.S. Federal Trade Commission (“FTC”) filed an enforcement action on January 3, 2020 regarding Axon’s May 2018 acquisition of Vievu LLC from Safariland LLC. The FTC alleges the merger was anticompetitive and adversely affected the body worn camera (“BWC”) and digital evidence management systems (“DEMS”) market for “large metropolitan police departments.” The stay of the administrative proceedings due to the COVID-19 pandemic lifted July 7, 2020 and fact and expert discovery is now complete. On October 2, 2020, the Ninth Circuit stayed the administrative hearing scheduled for October 13, 2020 pending decision on Axon’s appeal in the related matter discussed below. If ultimately successful, the FTC may require us to divest Vievu and other assets or take other remedial measures, any of which could be material to Axon. We are vigorously defending the matter. At this time, we cannot predict the eventual scope, duration, or outcome of the proceeding and accordingly we have not recorded any liability in the accompanying condensed consolidated financial statements. Separately, on January 3, 2020, Axon sued the FTC in federal court in the District of Arizona for declaratory and injunctive relief alleging the FTC’s structure and administrative processes violate Article II of the U.S. Constitution and our Fifth Amendment rights to due process and equal protection. On April 8, 2020, the district court dismissed the action, without prejudice, for lack of jurisdiction, requiring Axon to first bring its constitutional claims in the administrative case. Axon appealed that ruling to the Ninth Circuit (No. 20-15662), which granted expedited consideration and heard oral argument on July 17, 2020. The matter is now under advisement. In parallel to these matters, we are evaluating strategic alternatives to litigation, which we might pursue if determined to be in the best interests of shareholders and customers. This could include a divestiture of the Vievu entity and/or related assets and the licensure of certain intellectual and other intangible property. While we continue to believe the acquisition of Vievu was lawful and a benefit to Vievu’s customers, the cost, risk and distraction of protracted litigation merit consideration of settlement if achievable on terms agreeable to the FTC and us. General From time to time, we are notified that we may be a party to a lawsuit or that a claim is being made against us. It is our policy to not disclose the specifics of any claim or threatened lawsuit until the summons and complaint are actually served on us. After carefully assessing the claim, and assuming we determine that we are not at fault or we disagree with the damages or relief demanded, we vigorously defend any lawsuit filed against us. We record a liability when losses are deemed probable and reasonably estimable. When losses are deemed reasonably possible but not probable, we determine whether it is possible to provide an estimate of the amount of the loss or range of possible losses for the claim, if material for disclosure. In evaluating matters for accrual and disclosure purposes, we take into consideration factors such as our historical experience with matters of a similar nature, the specific facts and circumstances asserted, the likelihood of our prevailing, the availability of insurance, and the severity of any potential loss. We reevaluate and update accruals as matters progress over time. Based on our assessment of outstanding litigation and claims as of September 30, 2020, we have determined that it is not reasonably possible that these lawsuits will individually, or in the aggregate, materially affect our results of operations, financial condition or cash flows. However, the outcome of any litigation is inherently uncertain and there can be no assurance that any expense, liability or damages that may ultimately result from the resolution of these matters will be covered by our insurance or will not be in excess of amounts recognized or provided by insurance coverage and will not have a material adverse effect on our operating results, financial condition or cash flows. Off-Balance Sheet Arrangements Under certain circumstances, we use letters of credit and surety bonds to guarantee our performance under various contracts, principally in connection with the installation and integration of Axon cameras and related technologies. Certain of our letters of credit and surety bonds have stated expiration dates with others being released as the contractual performance terms are completed. At September 30, 2020, we had outstanding letters of credit of $6.1 million that are expected to expire in June 2021 and September 2021. We also had outstanding letters of credit and bank guarantees of $2.0 million that do not draw against our credit facility. The outstanding letters of credit are expected to expire in June 2021. Additionally, we had $24.0 million of outstanding surety bonds at September 30, 2020, with $0.1 million expiring in 2020, $2.7 million expiring in 2021, $3.2 million expiring in 2022, $7.5 million expiring in 2023 and the remaining $10.5 million expiring in 2024.

Employee Benefit Plans

Employee Benefit Plans	9 Months Ended
	Sep. 30, 2020
Retirement Benefits [Abstract]
Employee Benefit Plans	14. Employee Benefit Plans We have a defined contribution 401(k) plan for eligible employees, which is qualified under Sections 401(a) and 401(k) of the Internal Revenue Code of 1986, as amended. Employees are entitled to make tax-deferred contributions of up to the maximum amount allowed by law of their eligible compensation. We also have a non-qualified deferred compensation plan for certain executives, employees and non-employee directors through which participants may elect to postpone the receipt and taxation of a portion of their compensation, including stock-based compensation, received from us. The non-qualified deferred compensation plan allows eligible participants to defer up to 80% of their base salary and up to 100% of other types of compensation. The plan also allows for matching and discretionary employer contributions. Employee deferrals are deemed 100% vested upon contribution. Distributions from the plan are made upon retirement, death, separation of service, specified date or upon the occurrence of an unforeseeable emergency. Distributions can be paid in a variety of forms from lump sum to installments over a period of years. Participants in the plan are entitled to select from a wide variety of investments available under the plan and are allocated gains or losses based upon the performance of the investments selected by the participant. All gains or losses are allocated fully to plan participants and we do not guarantee a rate of return on deferred balances. Assets related to this plan consist of corporate-owned life insurance contracts and are included in other assets in the condensed consolidated balance sheets; see Note 8 for balances. Participants have no rights or claims with respect to any plan assets and any such assets are subject to the claims of our general creditors. Contributions to the plans are made by both the employee and us. Our contributions to the 401(k) plan are based on the level of employee contributions and are immediately vested. Future matching contributions to the plans are at our sole discretion. We also sponsor defined contribution plans in Australia, Finland, and the United Kingdom. Our matching contributions for all defined contribution plans were $1.3 million and $0.9 million for the three months ended September 30, 2020 and 2019, respectively and $4.1 million and $3.5 million for the nine months ended September 30, 2020 and 2019, respectively.

Segment Data

Segment Data	9 Months Ended
	Sep. 30, 2020
Segment Reporting [Abstract]
Segment Data	15. Segment Data Our operations are comprised of two reportable segments: the manufacture and sale of CEDs, batteries, accessories, extended warranties and other products and services (the “TASER” segment); and the software and sensors business, which includes the sale of devices, wearables, applications, cloud and mobile products, and services (collectively, the “Software and Sensors” segment). In both segments, we report sales of products and services. Service revenue in both segments includes sales related to Axon Evidence. In the Software and Sensors segment, service revenue also includes other recurring cloud-hosted software revenue and related professional services. Collectively, this revenue is sometimes referred to as "Axon Cloud revenue." Our Chief Executive Officer, who is the CODM, is not provided asset information or sales, general, and administrative expense by segment. Information relative to our reportable segments was as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, 2020 ​ Three Months Ended September 30, 2019 ​ ​ ​ ​ ​ Software and ​ ​ ​ ​ ​ ​ ​ Software and ​ ​ ​ ​ TASER Sensors Total TASER Sensors Total Net sales from products ​ $ 83,517 ​ $ 36,574 ​ $ 120,091 ​ $ 71,424 ​ $ 25,073 ​ $ 96,497 Net sales from services ​ 889 ​ 45,462 ​ 46,351 ​ 319 ​ 34,021 ​ 34,340 Net sales ​ 84,406 ​ 82,036 ​ 166,442 ​ 71,743 ​ 59,094 ​ 130,837 Cost of product sales ​ 31,297 ​ 26,501 ​ 57,798 ​ 26,504 ​ 15,941 ​ 42,445 Cost of service sales ​ — ​ 10,404 ​ 10,404 ​ — ​ 8,223 ​ 8,223 Cost of sales ​ 31,297 ​ 36,905 ​ 68,202 ​ 26,504 ​ 24,164 ​ 50,668 Gross margin ​ $ 53,109 ​ $ 45,131 ​ $ 98,240 ​ $ 45,239 ​ $ 34,930 ​ $ 80,169 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Research and development ​ $ 3,355 ​ $ 25,891 ​ $ 29,246 ​ $ 3,485 ​ $ 21,644 ​ $ 25,129 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Nine Months Ended September 30, 2020 ​ Nine Months Ended September 30, 2019 ​ ​ ​ ​ ​ Software and ​ ​ ​ ​ ​ ​ ​ Software and ​ ​ ​ ​ TASER Sensors Total TASER Sensors Total Net sales from products ​ $ 228,569 ​ ​ 97,565 ​ $ 326,134 ​ $ 197,148 ​ $ 67,829 ​ $ 264,977 Net sales from services ​ 2,222 ​ 126,507 ​ 128,729 ​ 558 ​ 93,474 ​ 94,032 Net sales ​ 230,791 ​ 224,072 ​ 454,863 ​ 197,706 ​ 161,303 ​ 359,009 Cost of product sales ​ 88,787 ​ 61,720 ​ 150,507 ​ 74,044 ​ 46,221 ​ 120,265 Cost of service sales ​ — ​ 29,331 ​ 29,331 ​ — ​ 24,098 ​ 24,098 Cost of sales ​ 88,787 ​ 91,051 ​ 179,838 ​ 74,044 ​ 70,319 ​ 144,363 Gross margin ​ $ 142,004 ​ $ 133,021 ​ $ 275,025 ​ $ 123,662 ​ $ 90,984 ​ $ 214,646 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Research and development ​ $ 10,149 ​ $ 75,038 ​ $ 85,187 ​ $ 10,284 ​ $ 61,692 ​ $ 71,976 ​

Organization and Summary of S_2

Organization and Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation and Use of Estimates	Basis of Presentation and Use of Estimates These unaudited condensed consolidated financial statements have been prepared pursuant to the rules and regulations of the SEC. Certain information related to our organization, significant accounting policies and footnote disclosures normally included in financial statements prepared in accordance with accounting principles generally accepted in the United States (“U.S. GAAP”) has been condensed or omitted. The accounting policies followed in the preparation of these unaudited condensed consolidated financial statements are consistent with those followed in our annual consolidated financial statements for the year ended December 31, 2019, as filed on Form 10-K, with the exception of our adoption of certain accounting pronouncements which we describe below. In the opinion of management, these unaudited condensed consolidated financial statements contain all material adjustments, consisting only of normal recurring adjustments, necessary to fairly state our financial position, results of operations and cash flows for the periods presented and the presentations and disclosures herein are adequate when read in conjunction with our Form 10-K for the year ended December 31, 2019. The results of operations for the three months and nine months ended September 30, 2020 and 2019 are not necessarily indicative of the results to be expected for the full year (or any other period). Significant estimates and assumptions in these unaudited condensed consolidated financial statements include: ● product warranty reserves, ● inventory valuation, ● revenue recognition, ● expected credit loss reserves, ● valuation of goodwill, intangible and long-lived assets, ● recognition, measurement and valuation of current and deferred income taxes, ● stock-based compensation, ● recognition and measurement of lease liabilities, ● recognition and measurement of contingencies and accrued litigation expense, and ● fair values of identified tangible and intangible assets acquired and liabilities assumed in business combinations. Actual results could differ materially from those estimates.
Segment Information	Segment Information Our operations are comprised of two reportable segments: the manufacture and sale of conducted electrical devices ("CEDs"), batteries, accessories, extended warranties and other products and services (the “TASER” segment); and the development, manufacture, and sale of software and sensors, which includes the sale of devices, wearables, applications, cloud and mobile products, and services (collectively, the “Software and Sensors” segment). In both segments, we report sales of products and services. Service revenue in both segments includes sales related to Axon Evidence. In the Software and Sensors segment, service revenue also includes other recurring cloud-hosted software revenue and related professional services. Collectively, this revenue is sometimes referred to as "Axon Cloud revenue." Reportable segments are determined based on discrete financial information reviewed by our Chief Executive Officer who is our chief operating decision maker ("CODM"). We organize and review operations based on products and services, and currently there are no operating segments that are aggregated. We perform an analysis of our reportable segments at least annually. Additional information related to our business segments is summarized in Note 15.
Geographic Information and Major Customers / Suppliers	Geographic Information and Major Customers / Suppliers For the three and nine months ended September 30, 2020 and 2019, no individual country outside the U.S. represented more than 10% of total net sales. Individual sales transactions in the international market are generally larger and occur more intermittently than in the domestic market due to the profile of our customers. For the three and nine months ended September 30, 2020 and 2019, no customer represented more than 10% of total net sales. At September 30, 2020 and December 31, 2019, no customer represented more than 10% of the aggregate balance of accounts and notes receivable and contract assets. We currently purchase both off the shelf and custom components, including, but not limited to, finished circuit boards, injection-molded plastic components, small machined parts, custom cartridge components, electronic components, and off the shelf sub-assemblies from suppliers located in the U.S., Australia, Canada, China, Germany, Japan, Mexico, and Taiwan. Although we currently obtain many of these components from single source suppliers, we own the injection molded component tooling, most of the designs, and the test fixtures used in their production for all custom components. As a result, we believe we could obtain alternative suppliers in most cases without incurring significant production delays. We also strategically hold safety stock levels on custom components to further reduce this risk. For off the shelf components, we believe that in most cases there are readily available alternative suppliers who can consistently meet our needs for these components. We acquire most of our components on a purchase order basis and do not have any significant long-term contracts with component suppliers.
Income per Common Share	Income per Common Share Basic income per common share is computed by dividing net income by the weighted average number of common shares outstanding during the periods presented. Diluted income per share reflects the potential dilution from outstanding stock options and unvested restricted stock units. The calculation of the weighted average number of shares outstanding and earnings per share are as follows (in thousands except per share data): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, ​ Nine Months Ended September 30, ​ 2020 2019 2020 2019 Numerator for basic and diluted earnings per share: ​ ​ ​ ​ Net income (loss) ​ $ (873) ​ $ 6,104 ​ $ (27,558) ​ $ 13,261 Denominator: ​ ​ ​ ​ ​ Weighted average shares outstanding ​ 63,496 ​ 59,278 ​ 61,159 ​ 59,128 Dilutive effect of stock-based awards ​ — ​ 781 ​ — ​ 810 Diluted weighted average shares outstanding ​ 63,496 ​ 60,059 ​ 61,159 ​ 59,938 Anti-dilutive stock-based awards excluded ​ 12,793 ​ 12,477 ​ 12,904 ​ 12,546 Net income (loss) per common share: ​ ​ ​ ​ ​ Basic ​ $ (0.01) ​ $ 0.10 ​ $ (0.45) ​ $ 0.22 Diluted ​ $ (0.01) ​ $ 0.10 ​ $ (0.45) ​ $ 0.22
Standard Warranties	Standard Warranties We warranty our CEDs, Axon cameras and certain related accessories from manufacturing defects on a limited basis for a period of one year after purchase and, thereafter, will repair or replace any defective unit for a fee. Estimated costs for the standard warranty are charged to cost of products sold when revenue is recorded for the related product. Future warranty costs are estimated based on historical data related to warranty claims and this rate is applied to current product sales. Historically, reserve amounts have been increased if management becomes aware of a component failure or other issue that could result in larger than anticipated warranty claims from customers. The warranty reserve is reviewed quarterly to verify that it sufficiently reflects the remaining warranty obligations based on the anticipated expenditures over the balance of the warranty obligation period, and adjustments are made when actual warranty claim experience differs from estimates. The warranty reserve is included in accrued liabilities on the accompanying condensed consolidated balance sheets. Changes in our estimated product warranty liabilities were as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Nine Months Ended September 30, ​ 2020 ​ 2019 Balance, beginning of period ​ $ 1,476 ​ $ 898 Utilization of reserve ​ (539) ​ (718) Warranty expense (benefit) ​ (192) ​ 891 Balance, end of period ​ $ 745 ​ $ 1,071
Fair Value Measurements and Financial Instruments	Fair Value Measurements and Financial Instruments We use the fair value framework that prioritizes the inputs to valuation techniques for measuring financial assets and liabilities measured on a recurring basis and for non-financial assets and liabilities when these items are re-measured. Fair value is considered to be the exchange price in an orderly transaction between market participants, to sell an asset or transfer a liability at the measurement date. The hierarchy below lists three levels of fair value based on the extent to which inputs used in measuring fair value are observable in the market. We categorize each of our fair value measurements in one of these three levels based on the lowest level input that is significant to the fair value measurement in its entirety. These levels are: ● Level 1 – Valuation techniques in which all significant inputs are unadjusted quoted prices from active markets for assets or liabilities that are identical to the assets or liabilities being measured. ● Level 2 – Valuation techniques in which significant inputs include quoted prices from active markets for assets or liabilities that are similar to the assets or liabilities being measured and/or quoted prices for assets or liabilities that are identical or similar to the assets or liabilities being measured from markets that are not active. Also, model-derived valuations in which all significant inputs and significant value drivers are observable in active markets are Level 2 valuation techniques. ● Level 3 – Valuation techniques in which one or more significant inputs or significant value drivers are unobservable. Unobservable inputs are valuation technique inputs that reflect our own assumptions about inputs that market participants would use in pricing an asset or liability. We have cash equivalents and investments, which at September 30, 2020 and December 31, 2019 were comprised of money market funds, certificates of deposit, commercial paper, corporate bonds, municipal bonds, U.S. Government agency bonds, U.S. Treasury bills, U.S. Treasury inflation-protected securities, and U.S. Treasury repurchase agreements. See additional disclosure regarding the fair value of our cash equivalents and investments in Note 3. Included in the balance of other assets as of September 30, 2020 and December 31, 2019 was $4.2 million and $4.2 million, respectively, related to corporate-owned life insurance policies which are used to fund our deferred compensation plan. We determine the fair value of insurance contracts by obtaining the cash surrender value of the contracts from the issuer, a Level 2 valuation technique. In March 2020, we made an investment of $4.7 million in preferred stock and recorded preferred stock warrants at a fair value of $2.6 million, which is also included in the balance of other assets as of September 30, 2020. The estimated fair value of the investments was determined based on Level 3 inputs. As of September 30, 2020, management estimated that the fair value of the investment equaled its carrying value. ​ Our financial instruments also include accounts and notes receivable, accounts payable and accrued liabilities. Due to the short-term nature of these instruments, their fair values approximate their carrying values on the balance sheet.
Restricted cash	Restricted Cash Restricted cash balances as of September 30, 2020 and December 31, 2019 included $0.1 million primarily related to funds held in an international bank account for a country in which we are required to maintain a minimum balance to operate. Approximately half of the balance was included in prepaid expenses and other current assets on our condensed consolidated balance sheets, with the remainder included in other assets.
Valuation of Goodwill, Intangibles and Long-lived Assets	Valuation of Goodwill, Intangibles and Long-lived Assets We evaluate whether events and circumstances have occurred that indicate the remaining estimated useful life of long-lived assets and identifiable intangible assets, excluding goodwill and intangible assets with indefinite useful lives, may warrant revision or that the remaining balance of these assets may not be recoverable. Such circumstances could include, but are not limited to, a change in the product mix, a change in the way products are created, produced or delivered, or a significant change in the way products are branded and marketed. In performing the review for recoverability, we estimate the future undiscounted cash flows expected to result from the use of the assets and their eventual disposition. The amount of the impairment loss, if impairment exists, is calculated based on the excess of the carrying amounts of the assets over their estimated fair value computed using discounted cash flows. We do not amortize goodwill and intangible assets with indefinite useful lives; rather such assets are required to be tested for impairment at least annually or sooner whenever events or changes in circumstances indicate that the assets may be impaired. We perform our annual goodwill and intangible asset impairment tests in the fourth quarter of each year.
Recently Issued Accounting Guidance	Recently Issued Accounting Guidance Recently Adopted Accounting Pronouncements In June 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments. ASU 2016-13 includes an impairment model (known as the current expected credit loss model) on financial instruments and other commitments that is based on expected losses rather than incurred losses. Under the new guidance, an entity recognizes as an allowance its estimate of expected credit losses, which the FASB believes will result in more timely recognition of such losses. The use of forecasted information is intended to incorporate more timely information in the estimate of expected credit loss. This ASU also requires enhanced disclosures relating to significant estimates and judgments used in estimating credit losses, as well as credit quality. Upon adoption, we recorded a noncash cumulative effect adjustment to retained earnings of $0.6 million, net of $0.2 million of income taxes, on the opening consolidated balance sheet as of January 1, 2020, reflecting an overall increase to the allowance for expected credit losses See Notes 3 and 4 for further disclosures related to Topic 326. ​ In August 2018, the FASB issued ASU 2018-13, Fair Value Measurement (Topic 820): Disclosure Framework—Changes to the Disclosure Requirements for Fair Value Measurement. ASU 2018-13 eliminates, adds and modifies certain disclosure requirements for fair value measurements. The amendments apply to the disclosures of changes in unrealized gains and losses, the range and weighted average of significant unobservable inputs used to develop Level 3 fair value measurements, and the narrative description of measurement uncertainty should be applied prospectively for only the most recent interim or annual period presented in the initial year of adoption. All other amendments should be applied retrospectively to all periods presented upon their effective date. Adoption of this ASU on January 1, 2020 did not have a material impact on our consolidated financial statements. ​ Effective the first quarter of 2021: ​ In December 2019, the FASB issued ASU 2019-12, Simplifying the Accounting for Income Taxes. The amendments in the ASU are effective for fiscal years beginning after December 15, 2020, including interim periods therein. Early adoption of the standard is permitted, including adoption in interim or annual periods for which financial statements have not yet been issued. Adoption of this ASU is not expected to have a material impact on our consolidated financial statements. ​ In January 2020, the FASB issued ASU No. 2020-01, Investments – Equity Securities (Topic 321), Investments – Equity Method and Joint Ventures (Topic 323), and Derivatives and Hedging (Topic 815) – Clarifying the Interactions Between Topic 321, Topic 323, and Topic 815 (a Consensus of the Emerging Issues Task Force). The guidance clarifies the interaction between ASU 2016-01, Financial Instruments – Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities and the ASU on equity method investments. ASU 2016-01 provides companies with an alternative to measure certain equity securities without a readily determinable fair value at cost, minus impairment, if any, unless an observable transaction for an identical or similar security occurs. ASU 2020-01 clarifies that for purposes of applying the Topic 321 measurement alternative, an entity should consider observable transactions that require it to either apply or discontinue the equity method of accounting under Topic 323, immediately before applying or upon discontinuing the equity method. In addition, the new ASU provides direction that a company should not consider whether the underlying securities would be accounted for under the equity method or the fair value option when it is determining the accounting for certain forward contracts and purchased options, upon either settlement or exercise. The amendments in this update become effective for fiscal years beginning after December 15, 2020, and interim periods within those fiscal years. Early adoption is permitted, and the amendments are to be applied prospectively. Adoption of this ASU is not expected to have a material impact on our consolidated financial statements.
Reclassification of Prior Year Presentation	Reclassification of Prior Year Presentation Certain prior year amounts, including the long-term portion of contract assets, have been reclassified for consistency with the current year presentation. These reclassifications are not material and had no effect on the reported results of operations.

Organization and Summary of S_3

Organization and Summary of Significant Accounting Policies (Tables)	9 Months Ended
	Sep. 30, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Weighted Average Number of Shares Outstanding and Income Per Share	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, ​ Nine Months Ended September 30, ​ 2020 2019 2020 2019 Numerator for basic and diluted earnings per share: ​ ​ ​ ​ Net income (loss) ​ $ (873) ​ $ 6,104 ​ $ (27,558) ​ $ 13,261 Denominator: ​ ​ ​ ​ ​ Weighted average shares outstanding ​ 63,496 ​ 59,278 ​ 61,159 ​ 59,128 Dilutive effect of stock-based awards ​ — ​ 781 ​ — ​ 810 Diluted weighted average shares outstanding ​ 63,496 ​ 60,059 ​ 61,159 ​ 59,938 Anti-dilutive stock-based awards excluded ​ 12,793 ​ 12,477 ​ 12,904 ​ 12,546 Net income (loss) per common share: ​ ​ ​ ​ ​ Basic ​ $ (0.01) ​ $ 0.10 ​ $ (0.45) ​ $ 0.22 Diluted ​ $ (0.01) ​ $ 0.10 ​ $ (0.45) ​ $ 0.22
Summary of Changes in Estimated Product Warranty Liabilities	Changes in our estimated product warranty liabilities were as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Nine Months Ended September 30, ​ 2020 ​ 2019 Balance, beginning of period ​ $ 1,476 ​ $ 898 Utilization of reserve ​ (539) ​ (718) Warranty expense (benefit) ​ (192) ​ 891 Balance, end of period ​ $ 745 ​ $ 1,071

Revenues (Tables)

Revenues (Tables)	9 Months Ended
	Sep. 30, 2020
Revenue from Contract with Customer [Abstract]
Summary of Revenue by Product and Service Offering and Geography	The following tables present our revenues by primary product and service offering (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, 2020 ​ Three Months Ended September 30, 2019 ​ ​ ​ Software and ​ ​ ​ ​ Software and ​ ​ ​ ​ TASER ​ Sensors ​ Total ​ TASER ​ Sensors ​ Total TASER 7 ​ $ 21,702 ​ $ — ​ $ 21,702 ​ $ 20,214 ​ $ — ​ $ 20,214 TASER X26P ​ 9,766 ​ — ​ 9,766 ​ 11,578 ​ — ​ 11,578 TASER X2 ​ 14,494 ​ — ​ 14,494 ​ 13,241 ​ — ​ 13,241 TASER Pulse ​ 2,981 ​ — ​ 2,981 ​ 1,132 ​ — ​ 1,132 Cartridges ​ 26,335 ​ — ​ 26,335 ​ 18,901 ​ — ​ 18,901 Axon Body ​ — ​ 15,978 ​ 15,978 ​ — ​ 6,763 ​ 6,763 Axon Flex ​ — ​ 1,589 ​ 1,589 ​ — ​ 1,670 ​ 1,670 Axon Fleet ​ — ​ 4,215 ​ 4,215 ​ — ​ 4,341 ​ 4,341 Axon Dock ​ — ​ 5,708 ​ 5,708 ​ — ​ 3,358 ​ 3,358 Axon Evidence and cloud services ​ 692 ​ 45,450 ​ 46,142 ​ 218 ​ 34,022 ​ 34,240 Extended warranties ​ 5,265 ​ 6,514 ​ 11,779 ​ 4,543 ​ 4,714 ​ 9,257 Other ​ 3,171 ​ 2,582 ​ 5,753 ​ 1,916 ​ 4,226 ​ 6,142 Total ​ $ 84,406 ​ $ 82,036 ​ $ 166,442 ​ $ 71,743 ​ $ 59,094 ​ $ 130,837 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Nine Months Ended September 30, 2020 ​ Nine Months Ended September 30, 2019 ​ ​ ​ Software and ​ ​ ​ ​ Software and ​ ​ ​ ​ TASER ​ Sensors ​ Total ​ TASER ​ Sensors ​ Total TASER 7 ​ $ 48,616 ​ $ — ​ $ 48,616 ​ $ 39,466 ​ $ — ​ $ 39,466 TASER X26P ​ 30,338 ​ — ​ 30,338 ​ 37,832 ​ — ​ 37,832 TASER X2 ​ 45,401 ​ — ​ 45,401 ​ 40,413 ​ — ​ 40,413 TASER Pulse ​ 6,374 ​ — ​ 6,374 ​ 2,920 ​ — ​ 2,920 Cartridges ​ 76,732 ​ — ​ 76,732 ​ 57,354 ​ — ​ 57,354 Axon Body ​ — ​ 40,645 ​ 40,645 ​ — ​ 18,820 ​ 18,820 Axon Flex ​ — ​ 3,452 ​ 3,452 ​ — ​ 4,517 ​ 4,517 Axon Fleet ​ — ​ 13,088 ​ 13,088 ​ — ​ 10,977 ​ 10,977 Axon Dock ​ — ​ 14,714 ​ 14,714 ​ — ​ 9,401 ​ 9,401 Axon Evidence and cloud services ​ 1,776 ​ 126,495 ​ 128,271 ​ 363 ​ 93,461 ​ 93,824 Extended warranties ​ 15,340 ​ 17,707 ​ 33,047 ​ 13,341 ​ 14,064 ​ 27,405 Other ​ 6,214 ​ 7,971 ​ 14,185 ​ 6,017 ​ 10,063 ​ 16,080 Total ​ $ 230,791 ​ $ 224,072 ​ $ 454,863 ​ $ 197,706 ​ $ 161,303 ​ $ 359,009 ​ ​ The following table presents our revenues disaggregated by geography (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, ​ ​ Nine Months Ended September 30, ​ ​ 2020 ​ ​ 2019 ​ ​ 2020 ​ 2019 United States $ 143,380 86 % ​ $ 110,809 85 % ​ $ 368,390 81 % $ 298,736 83 % Other countries ​ 23,062 14 ​ ​ 20,028 15 ​ ​ 86,473 19 ​ 60,273 17 ​ Total ​ $ 166,442 100 % ​ $ 130,837 100 % ​ $ 454,863 100 % $ 359,009 100 %
Contract with Customer, Assets and Liabilities	The following table presents our contract assets, contract liabilities and certain information related to these balances as of and for the nine months ended September 30, 2020 (in thousands): ​ ​ ​ ​ ​ ​ September 30, 2020 Contract assets, net ​ $ 78,124 Contract liabilities (deferred revenue) ​ 242,464 Revenue recognized in the period from: ​ Amounts included in contract liabilities at the beginning of the period ​ 113,422 ​ Contract liabilities (deferred revenue) consisted of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, 2020 ​ December 31, 2019 ​ Current Long-Term Total Current Long-Term Total Warranty: ​ ​ ​ ​ ​ ​ TASER ​ $ 13,267 ​ $ 14,824 ​ $ 28,091 ​ $ 12,716 ​ $ 16,378 ​ $ 29,094 Software and Sensors ​ 12,328 ​ 3,983 ​ 16,311 ​ 9,852 ​ 5,156 ​ 15,008 ​ ​ 25,595 ​ 18,807 ​ 44,402 ​ 22,568 ​ 21,534 ​ 44,102 Hardware: ​ ​ ​ ​ ​ ​ TASER ​ 15,621 ​ 12,124 ​ 27,745 ​ 9,569 ​ 15,468 ​ 25,037 Software and Sensors ​ 27,225 ​ 40,443 ​ 67,668 ​ 22,235 ​ 33,759 ​ 55,994 ​ ​ 42,846 ​ 52,567 ​ 95,413 ​ 31,804 ​ 49,227 ​ 81,031 Services: ​ ​ ​ ​ ​ ​ TASER ​ 722 ​ 1,091 ​ 1,813 ​ 293 ​ 765 ​ 1,058 Software and Sensors ​ 85,568 ​ 15,268 ​ 100,836 ​ 63,199 ​ 16,410 ​ 79,609 ​ ​ ​ 86,290 ​ ​ 16,359 ​ ​ 102,649 ​ ​ 63,492 ​ ​ 17,175 ​ ​ 80,667 Total ​ $ 154,731 ​ $ 87,733 ​ $ 242,464 ​ $ 117,864 ​ $ 87,936 ​ $ 205,800 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, 2020 ​ December 31, 2019 ​ Current Long-Term Total Current Long-Term Total TASER ​ $ 29,610 ​ $ 28,039 ​ $ 57,649 ​ $ 22,578 ​ $ 32,611 ​ $ 55,189 Software and Sensors ​ 125,121 ​ 59,694 ​ 184,815 ​ 95,286 ​ 55,325 ​ 150,611 Total ​ $ 154,731 ​ $ 87,733 ​ $ 242,464 ​ $ 117,864 ​ $ 87,936 ​ $ 205,800

Cash, Cash Equivalents and In_2

Cash, Cash Equivalents and Investments (Tables)	9 Months Ended
	Sep. 30, 2020
Cash and Cash Equivalents [Abstract]
Summary of Cash, Cash Equivalents and Held-to-Maturity Investments by Type	The following tables summarize our cash, cash equivalents, and held-to-maturity investments at September 30, 2020 and December 31, 2019 (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of September 30, 2020 ​ ​ ​ Gross Gross ​ ​ Cash and ​ ​ ​ ​ ​ ​ Amortized ​ Unrealized ​ Unrealized ​ ​ ​ ​ ​ Cash ​ Short-Term ​ Long-Term ​ ​ Cost ​ Gains ​ Losses ​ Fair Value ​ ​ Equivalents ​ Investments ​ Investments Cash ​ $ 91,499 ​ $ — ​ $ — ​ $ 91,499 ​ ​ $ 91,499 ​ $ — ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Level 1: ​ ​ ​ ​ ​ ​ ​ ​ Money market funds ​ 31,298 ​ — ​ — ​ 31,298 ​ ​ 31,298 ​ — ​ — Agency bonds ​ 68,111 ​ 141 ​ — ​ 68,252 ​ ​ — ​ 24,610 ​ 43,501 Treasury bills ​ ​ 57,284 ​ ​ 3 ​ ​ — ​ ​ 57,287 ​ ​ ​ 5,499 ​ ​ 51,785 ​ ​ — Subtotal ​ 156,693 ​ 144 ​ — ​ 156,837 ​ ​ 36,797 ​ 76,395 ​ 43,501 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Level 2: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ State and municipal obligations ​ 63,363 ​ ​ 49 ​ ​ (14) ​ ​ 63,398 ​ ​ ​ 1,001 ​ ​ 49,441 ​ ​ 12,921 Certificates of deposit ​ ​ 1,900 ​ ​ — ​ ​ — ​ ​ 1,900 ​ ​ ​ — ​ ​ 1,400 ​ ​ 500 Corporate bonds ​ ​ 222,817 ​ ​ 389 ​ ​ (166) ​ ​ 223,040 ​ ​ ​ 2,908 ​ ​ 156,178 ​ ​ 63,731 U.S. Treasury repurchase agreements ​ ​ 43,800 ​ ​ — ​ ​ — ​ ​ 43,800 ​ ​ ​ 43,800 ​ ​ — ​ ​ — Treasury inflation-protected securities ​ 3,270 ​ ​ 24 ​ ​ — ​ ​ 3,294 ​ ​ ​ — ​ ​ 3,270 ​ ​ — Commercial paper ​ 44,356 ​ ​ — ​ ​ — ​ ​ 44,356 ​ ​ ​ — ​ ​ 44,356 ​ ​ — Subtotal ​ 379,506 ​ ​ 462 ​ ​ (180) ​ ​ 379,788 ​ ​ ​ 47,709 ​ ​ 254,645 ​ ​ 77,152 Total ​ $ 627,698 ​ $ 606 ​ $ (180) ​ $ 628,124 ​ ​ $ 176,005 ​ $ 331,040 ​ $ 120,653 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, 2019 ​ ​ ​ Gross Gross ​ ​ Cash and ​ ​ ​ ​ ​ ​ Amortized ​ Unrealized ​ Unrealized ​ ​ ​ ​ ​ Cash ​ Short-Term ​ Long-Term ​ ​ Cost ​ Gains ​ Losses ​ Fair Value ​ ​ Equivalents ​ Investments ​ Investments Cash ​ $ 103,319 ​ $ — ​ $ — ​ $ 103,319 ​ ​ $ 103,319 ​ $ — ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Level 1: ​ ​ ​ ​ ​ ​ ​ ​ Money market funds ​ 8,845 ​ — ​ — ​ 8,845 ​ ​ 8,845 ​ — ​ — Agency bonds ​ 32,869 ​ 14 ​ (4) ​ 32,879 ​ ​ — ​ 15,131 ​ 17,738 Subtotal ​ 41,714 ​ 14 ​ (4) ​ 41,724 ​ ​ 8,845 ​ 15,131 ​ 17,738 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Level 2: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ State and municipal obligations ​ ​ 25,038 ​ ​ 8 ​ ​ — ​ ​ 25,046 ​ ​ ​ — ​ ​ 21,560 ​ ​ 3,478 Certificates of deposit ​ ​ 1,400 ​ ​ — ​ ​ — ​ ​ 1,400 ​ ​ ​ — ​ ​ 1,400 ​ ​ — Corporate bonds ​ ​ 135,175 ​ ​ 71 ​ ​ (30) ​ ​ 135,216 ​ ​ ​ 886 ​ ​ 113,241 ​ ​ 21,048 U.S. Treasury repurchase agreements ​ ​ 57,200 ​ ​ — ​ ​ — ​ ​ 57,200 ​ ​ ​ 57,200 ​ ​ — ​ ​ — Treasury inflation-protected securities ​ ​ 3,235 ​ ​ 14 ​ ​ — ​ ​ 3,249 ​ ​ ​ — ​ ​ — ​ ​ 3,235 Commercial paper ​ ​ 29,202 ​ ​ — ​ ​ — ​ ​ 29,202 ​ ​ ​ 2,000 ​ ​ 27,202 ​ ​ — Subtotal ​ ​ 251,250 ​ ​ 93 ​ ​ (30) ​ ​ 251,313 ​ ​ ​ 60,086 ​ ​ 163,403 ​ ​ 27,761 Total ​ $ 396,283 ​ $ 107 ​ $ (34) ​ $ 396,356 ​ ​ $ 172,250 ​ $ 178,534 ​ $ 45,499

Expected Credit Losses (Tables)

Expected Credit Losses (Tables)	9 Months Ended
	Sep. 30, 2020
Expected Credit Losses
Schedule of roll-forward of allowance for credit losses	The following table provides a roll-forward of the allowance for expected credit losses that is deducted from the amortized cost basis of accounts receivable, notes receivable, and contract assets to present the net amount expected to be collected (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Nine Months Ended September 30, 2020 ​ ​ ​ United States ​ ​ Other countries ​ ​ Total Balance, beginning of period ​ $ 1,395 ​ $ 172 ​ $ 1,567 Adoption of Topic 326, cumulative-effect adjustment to retained earnings ​ ​ 767 ​ ​ 1 ​ ​ 768 Provision for expected credit losses ​ ​ 578 ​ ​ 115 ​ ​ 693 Amounts written off charged against the allowance ​ ​ (61) ​ ​ (2) ​ ​ (63) Other, including dispositions and foreign currency translation ​ - ​ (3) ​ (3) Balance, end of period ​ $ 2,679 ​ $ 283 ​ $ 2,962
Schedule of allowance for expected credit losses for each type of customer receivable	​ ​ ​ ​ ​ ​ ​ September 30, ​ 2020 Accounts receivable and notes receivable, current ​ $ 1,787 Contract assets, net ​ 711 Long-term notes receivable, net of current portion ​ 464 Total allowance for expected credit losses on customer receivables ​ $ 2,962

Inventory (Tables)

Inventory (Tables)	9 Months Ended
	Sep. 30, 2020
Inventory Disclosure [Abstract]
Inventory	​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, 2020 December 31, 2019 Raw materials ​ $ 43,082 ​ $ 20,789 Finished goods ​ 54,528 ​ 18,056 Total inventory ​ $ 97,610 ​ $ 38,845

Property and Equipment (Tables)

Property and Equipment (Tables)	9 Months Ended
	Sep. 30, 2020
Property, Plant and Equipment [Abstract]
Summary of Property and Equipment	Property and equipment consisted of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Estimated ​ ​ ​ ​ ​ ​ ​ Useful Life September 30, 2020 December 31, 2019 Land ​ N/A ​ $ 57,052 ​ $ 2,900 Building and leasehold improvements ​ 3-39 years ​ ​ 20,330 ​ ​ 20,089 Production equipment ​ 3-7 years ​ 32,919 ​ 29,961 Computers, equipment and software ​ 3-5 years ​ 7,839 ​ 8,126 Furniture and office equipment ​ 5-7 years ​ 6,014 ​ 6,514 Vehicles ​ 5 years ​ 1,782 ​ 1,753 Website development costs ​ 3 years ​ 204 ​ 204 Capitalized internal-use software development costs ​ 3 years ​ 3,670 ​ 3,670 Construction-in-process ​ N/A ​ 17,546 ​ 12,385 Total cost ​ ​ ​ 147,356 ​ 85,602 Less: Accumulated depreciation ​ ​ ​ (44,638) ​ (41,832) Property and equipment, net ​ ​ $ 102,718 ​ $ 43,770

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	9 Months Ended
	Sep. 30, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Goodwill	The changes in the carrying amount of goodwill for the nine months ended September 30, 2020 were as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Software and ​ ​ ​ ​ TASER ​ Sensors ​ Total Balance, beginning of period ​ $ 1,354 ​ $ 23,659 ​ $ 25,013 Foreign currency translation adjustments ​ — ​ (1) ​ (1) Balance, end of period ​ $ 1,354 ​ $ 23,658 ​ $ 25,012
Indefinite-Lived Intangible Assets Other than Goodwill	Intangible assets (other than goodwill) consisted of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, 2020 ​ December 31, 2019 ​ ​ Gross ​ ​ Net Gross ​ ​ Net ​ ​ Useful ​ Carrying ​ Accumulated ​ Carrying ​ Carrying ​ Accumulated ​ Carrying ​ ​ Life ​ Amount ​ Amortization ​ Amount ​ Amount ​ Amortization ​ Amount Amortizable (definite-lived) intangible assets: ​ ​ ​ ​ ​ Domain names 5‑10 years ​ $ 3,161 ​ $ (1,263) ​ $ 1,898 ​ $ 3,161 ​ $ (1,035) ​ $ 2,126 Issued patents 5‑25 years ​ 3,216 ​ (1,510) ​ 1,706 ​ 3,271 ​ (1,339) ​ 1,932 Issued trademarks 3‑15 years ​ 1,200 ​ (573) ​ 627 ​ 1,166 ​ (678) ​ 488 Customer relationships 4‑8 years ​ 3,712 ​ (1,784) ​ 1,928 ​ 3,721 ​ (1,416) ​ 2,305 Non-compete agreements 3‑4 years ​ 452 ​ (419) ​ 33 ​ 450 ​ (404) ​ 46 Developed technology 3‑5 years ​ 10,660 ​ (8,167) ​ 2,493 ​ 10,660 ​ (6,528) ​ 4,132 Re-acquired distribution rights 2 years ​ 2,042 ​ (2,042) ​ — ​ 2,009 ​ (2,009) ​ — Total amortizable ​ 24,443 ​ (15,758) ​ 8,685 ​ 24,438 ​ (13,409) ​ 11,029 Non-amortizable (indefinite-lived) intangible assets: ​ ​ ​ ​ TASER trademark ​ 900 ​ ​ 900 ​ 900 ​ ​ 900 Patents and trademarks pending ​ 675 ​ ​ 675 ​ 842 ​ ​ 842 Total non-amortizable ​ 1,575 ​ ​ 1,575 ​ 1,742 ​ ​ 1,742 Total intangible assets ​ $ 26,018 ​ $ (15,758) ​ $ 10,260 ​ $ 26,180 ​ $ (13,409) ​ $ 12,771
Finite-Lived Intangible Assets Other than Goodwill	Intangible assets (other than goodwill) consisted of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, 2020 ​ December 31, 2019 ​ ​ Gross ​ ​ Net Gross ​ ​ Net ​ ​ Useful ​ Carrying ​ Accumulated ​ Carrying ​ Carrying ​ Accumulated ​ Carrying ​ ​ Life ​ Amount ​ Amortization ​ Amount ​ Amount ​ Amortization ​ Amount Amortizable (definite-lived) intangible assets: ​ ​ ​ ​ ​ Domain names 5‑10 years ​ $ 3,161 ​ $ (1,263) ​ $ 1,898 ​ $ 3,161 ​ $ (1,035) ​ $ 2,126 Issued patents 5‑25 years ​ 3,216 ​ (1,510) ​ 1,706 ​ 3,271 ​ (1,339) ​ 1,932 Issued trademarks 3‑15 years ​ 1,200 ​ (573) ​ 627 ​ 1,166 ​ (678) ​ 488 Customer relationships 4‑8 years ​ 3,712 ​ (1,784) ​ 1,928 ​ 3,721 ​ (1,416) ​ 2,305 Non-compete agreements 3‑4 years ​ 452 ​ (419) ​ 33 ​ 450 ​ (404) ​ 46 Developed technology 3‑5 years ​ 10,660 ​ (8,167) ​ 2,493 ​ 10,660 ​ (6,528) ​ 4,132 Re-acquired distribution rights 2 years ​ 2,042 ​ (2,042) ​ — ​ 2,009 ​ (2,009) ​ — Total amortizable ​ 24,443 ​ (15,758) ​ 8,685 ​ 24,438 ​ (13,409) ​ 11,029 Non-amortizable (indefinite-lived) intangible assets: ​ ​ ​ ​ TASER trademark ​ 900 ​ ​ 900 ​ 900 ​ ​ 900 Patents and trademarks pending ​ 675 ​ ​ 675 ​ 842 ​ ​ 842 Total non-amortizable ​ 1,575 ​ ​ 1,575 ​ 1,742 ​ ​ 1,742 Total intangible assets ​ $ 26,018 ​ $ (15,758) ​ $ 10,260 ​ $ 26,180 ​ $ (13,409) ​ $ 12,771
Estimated Amortization Expense of Intangible Assets	​ ​ ​ ​ ​ 2020 remaining $ 831 2021 ​ 2,879 2022 ​ 1,277 2023 ​ 982 2024 ​ 899 2025 ​ 632 Thereafter ​ 1,185 Total ​ $ 8,685

Other Long-Term Assets (Tables)

Other Long-Term Assets (Tables)	9 Months Ended
	Sep. 30, 2020
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Schedule of Other Long-Term Assets	Other long-term assets consisted of the following at September 30, 2020 and December 31, 2019 (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, 2020 December 31, 2019 Cash surrender value of corporate-owned life insurance policies ​ $ 4,225 ​ $ 4,214 Deferred commissions (1) ​ 27,263 ​ 22,068 Restricted cash ​ 59 ​ 56 Operating lease assets ​ 22,368 ​ 9,653 Investment in unconsolidated affiliate (2)(4) ​ ​ 4,700 ​ ​ — Warrants for unconsolidated affiliate (3)(4) ​ ​ 2,588 ​ ​ — Prepaid expenses, deposits and other ​ 6,085 ​ 4,190 Total other long-term assets ​ $ 67,288 ​ $ 40,181 (1) Represents the incremental costs of obtaining contracts with customers, which consist primarily of sales commissions. These costs are ascribed to or allocated to the underlying performance obligations in the contracts and amortized consistent with the recognition timing of the revenue for the underlying performance obligations. (2) In March 2020, we made an investment in and entered into a commercial partnership agreement with Flock Group Inc., a provider of advanced security for neighborhoods and law enforcement. Our $4.7 million investment resulted in our ownership of approximately 5% of the outstanding equity interests of this company. We account for this investment under the ASC 321 measurement alternative for equity securities without readily determinable fair values, as there are no quoted market prices for the investment. The investment is measured at cost less impairment, adjusted for observable price changes and is assessed for impairment whenever events or changes in circumstances indicate that the carrying amount may not be recoverable. As of September 30, 2020, no impairment was recorded for the investment. (3) In conjunction with the equity investment in and commercial partnership with Flock Group Inc., we have the ability to commit additional capital over time through warrants where the exercisability and exercise prices are conditional on the achievement of certain partnership performance metrics. The fair value of the preferred stock warrants was estimated at $2.6 million using Monte Carlo simulation. ​ (4) In October 2020, we made an additional $2.1 million investment in Flock Group Inc. After this incremental investment, we hold approximately 4% of the outstanding equity interests. The issuance of new equity by Flock Group Inc. to us and other investors represents an observable price change for our existing investment and related warrants which will be reflected in the consolidated financial statements for the period ending December 31, 2020.

Accrued Liabilities (Tables)

Accrued Liabilities (Tables)	9 Months Ended
	Sep. 30, 2020
Payables and Accruals [Abstract]
Accrued Liabilities	Accrued liabilities consisted of the following at September 30, 2020 and December 31, 2019 (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, 2020 December 31, 2019 Accrued salaries, benefits and bonus ​ $ 25,365 ​ $ 24,737 Accrued professional, consulting and lobbying fees ​ 11,483 ​ 3,235 Accrued warranty expense ​ 745 ​ 1,476 Accrued income and other taxes ​ 18,086 ​ 3,362 Accrued inventory in transit ​ ​ 10,185 ​ ​ 4,156 Other accrued expenses ​ 8,250 ​ 8,035 Accrued liabilities ​ $ 74,114 ​ $ 45,001

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	9 Months Ended
	Sep. 30, 2020
Equity [Abstract]
Equity Compensation Goals	​ ​ ​ ​ ​ Eight Separate Adjusted EBITDA (CEO Eight Separate Revenue Goals (1) ​ Performance Award) Goals (in thousands) ​ (in thousands) Goal #1, $710,058 Goal #9, $125,000 Goal #2, $860,058 Goal #10, $155,000 Goal #3, $1,010,058 Goal #11, $175,000 Goal #4, $1,210,058 Goal #12, $190,000 Goal #5, $1,410,058 Goal #13, $200,000 Goal #6, $1,610,058 Goal #14, $210,000 Goal #7, $1,810,058 Goal #15, $220,000 Goal #8, $2,010,058 Goal #16, $230,000 (1) In connection with the business acquisition that was completed during the three months ended June 30, 2018, the revenue goals were adjusted for the acquiree’s Target Revenue, as defined in the CEO Performance Award agreement.
Summary of Restricted Stock Unit Activity	The following table summarizes RSU activity for the nine months ended September 30, 2020 (number of units and aggregate intrinsic value in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Number of Weighted Average Aggregate ​ ​ Units ​ Grant-Date Fair Value ​ Intrinsic Value Units outstanding, beginning of year 1,249 ​ $ 45.47 ​ Granted 279 ​ 78.86 ​ Released (394) ​ 39.00 ​ Forfeited (85) ​ 50.82 ​ Units outstanding, end of period 1,049 ​ 56.34 ​ $ 95,112
Summary of Performance Stock Unit Activity	The following table summarizes Performance Stock Units (“PSUs”) activity, inclusive of XSUs, for the nine months ended September 30, 2020 (number of units and aggregate intrinsic value in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Number of Weighted Average Aggregate ​ ​ Units ​ Grant-Date Fair Value ​ Intrinsic Value Units outstanding, beginning of year 6,033 ​ $ 34.47 ​ Granted 380 ​ 55.94 ​ Released (160) ​ 25.20 ​ Forfeited (474) ​ 43.09 ​ Units outstanding, end of period 5,779 ​ 35.43 ​ $ 524,180
Summary of the Stock Option Activity	The following table summarizes stock option activity for the nine months ended September 30, 2020 (number of units and aggregate intrinsic value in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ ​ ​ ​ ​ Weighted ​ Average ​ ​ ​ ​ ​ Number ​ Average ​ Remaining ​ ​ ​ ​ ​ of ​ Exercise ​ Contractual ​ Aggregate ​ ​ Options ​ Price ​ Life (years) ​ Intrinsic Value Options outstanding, beginning of year 6,431 ​ $ 28.34 ​ Granted — ​ — ​ Exercised (65) ​ 4.52 ​ Expired / terminated — ​ — ​ Options outstanding, end of period 6,366 ​ 28.58 7.41 ​ $ 395,449 Options exercisable, end of period 1 ​ 4.70 0.26 ​ 2
Stock-Based Compensation	The following table summarizes the composition of stock-based compensation expense for the three and nine months ended September 30, 2020 and 2019 (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, ​ Nine Months Ended September 30, ​ 2020 2019 2020 2019 Cost of products sold and services delivered ​ $ 744 ​ $ 312 ​ $ 2,170 ​ $ 775 Sales, general and administrative expenses ​ 19,117 ​ 9,508 ​ 60,853 ​ 19,130 Research and development expenses ​ 6,233 ​ 3,843 ​ 17,101 ​ 10,290 Total stock-based compensation expense ​ $ 26,094 ​ $ 13,663 ​ $ 80,124 ​ $ 30,195

Segment Data (Tables)

Segment Data (Tables)	9 Months Ended
	Sep. 30, 2020
Segment Reporting [Abstract]
Summary of Operational Information Relative to the Company's Reportable Segments	Information relative to our reportable segments was as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, 2020 ​ Three Months Ended September 30, 2019 ​ ​ ​ ​ ​ Software and ​ ​ ​ ​ ​ ​ ​ Software and ​ ​ ​ ​ TASER Sensors Total TASER Sensors Total Net sales from products ​ $ 83,517 ​ $ 36,574 ​ $ 120,091 ​ $ 71,424 ​ $ 25,073 ​ $ 96,497 Net sales from services ​ 889 ​ 45,462 ​ 46,351 ​ 319 ​ 34,021 ​ 34,340 Net sales ​ 84,406 ​ 82,036 ​ 166,442 ​ 71,743 ​ 59,094 ​ 130,837 Cost of product sales ​ 31,297 ​ 26,501 ​ 57,798 ​ 26,504 ​ 15,941 ​ 42,445 Cost of service sales ​ — ​ 10,404 ​ 10,404 ​ — ​ 8,223 ​ 8,223 Cost of sales ​ 31,297 ​ 36,905 ​ 68,202 ​ 26,504 ​ 24,164 ​ 50,668 Gross margin ​ $ 53,109 ​ $ 45,131 ​ $ 98,240 ​ $ 45,239 ​ $ 34,930 ​ $ 80,169 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Research and development ​ $ 3,355 ​ $ 25,891 ​ $ 29,246 ​ $ 3,485 ​ $ 21,644 ​ $ 25,129 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Nine Months Ended September 30, 2020 ​ Nine Months Ended September 30, 2019 ​ ​ ​ ​ ​ Software and ​ ​ ​ ​ ​ ​ ​ Software and ​ ​ ​ ​ TASER Sensors Total TASER Sensors Total Net sales from products ​ $ 228,569 ​ ​ 97,565 ​ $ 326,134 ​ $ 197,148 ​ $ 67,829 ​ $ 264,977 Net sales from services ​ 2,222 ​ 126,507 ​ 128,729 ​ 558 ​ 93,474 ​ 94,032 Net sales ​ 230,791 ​ 224,072 ​ 454,863 ​ 197,706 ​ 161,303 ​ 359,009 Cost of product sales ​ 88,787 ​ 61,720 ​ 150,507 ​ 74,044 ​ 46,221 ​ 120,265 Cost of service sales ​ — ​ 29,331 ​ 29,331 ​ — ​ 24,098 ​ 24,098 Cost of sales ​ 88,787 ​ 91,051 ​ 179,838 ​ 74,044 ​ 70,319 ​ 144,363 Gross margin ​ $ 142,004 ​ $ 133,021 ​ $ 275,025 ​ $ 123,662 ​ $ 90,984 ​ $ 214,646 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Research and development ​ $ 10,149 ​ $ 75,038 ​ $ 85,187 ​ $ 10,284 ​ $ 61,692 ​ $ 71,976

Organization and Summary of S_4

Organization and Summary of Significant Accounting Policies - Narrative (Details) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2020USD ($)countrycustomer	Sep. 30, 2019customercountry	Sep. 30, 2020USD ($)customercountrysegment	Sep. 30, 2019customercountry	Dec. 31, 2019USD ($)customer	Mar. 31, 2020USD ($)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Number of reportable segments | segment			2
Warranty period			1 year
Corporate owned life insurance policies fair value	$ 4,225		$ 4,225		$ 4,214
Restricted cash balance	59		59		56
Investment in unconsolidated affiliate	4,700		4,700			$ 4,700
Warrants for unconsolidated affiliate	2,588		2,588
Prepaid Expenses and Other Current Assets
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Restricted cash balance	$ 100		$ 100		$ 100
Net Sales | Geographic Concentration Risk
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Number of countries outside the U.S. representing more than 10% of total net sales | country	0	0	0	0
Net Sales | Customer Concentration Risk
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Number of major customers | customer	0	0	0	0
Accounts and notes receivable and contract assets | Customer Concentration Risk
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Number of major customers | customer			0		0

Organization and Summary of S_5

Organization and Summary of Significant Accounting Policies - Weighted Average Number of Shares Outstanding and Income Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Sep. 30, 2019
Numerator for basic and diluted earnings per share:
Net income (loss)	$ (873)	$ (30,759)	$ 4,074	$ 6,104	$ 738	$ 6,419	$ (27,558)	$ 13,261
Denominator:
Weighted average shares outstanding (in shares)	63,496			59,278			61,159	59,128
Dilutive effect of stock-based awards (in shares)				781				810
Diluted weighted average shares outstanding (in shares)	63,496			60,059			61,159	59,938
Anti-dilutive stock-based awards excluded (in shares)	12,793			12,477			12,904	12,546
Net income (loss) per common share:
Basic (in dollars per share)	$ (0.01)			$ 0.10			$ (0.45)	$ 0.22
Diluted (in dollars per share)	$ (0.01)			$ 0.10			$ (0.45)	$ 0.22

Organization and Summary of S_6

Organization and Summary of Significant Accounting Policies - Summary of Changes in Estimated Product Warranty Liabilities (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Movement in Standard and Extended Product Warranty Accrual, Increase (Decrease) [Roll Forward]
Balance, beginning of period	$ 1,476	$ 898
Utilization of reserve	(539)	(718)
Warranty expense (benefit)	(192)	891
Balance, end of period	$ 745	$ 1,071

Organization and Summary of S_7

Organization and Summary of Significant Accounting Policies - Adjustments to Opening Balance Sheet (Details) - USD ($) $ in Thousands	Jan. 01, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect adjustment to retained earnings		$ (895,153)	$ (869,813)	$ (559,590)	$ (543,495)	$ (507,647)	$ (488,927)	$ (480,539)	$ (467,324)
Impact of Adoption of Topic 326 on opening balance sheet
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect adjustment, income taxes	$ 200
Cumulative Effect, Period of Adoption, Adjustment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect adjustment to retained earnings					$ 640
Cumulative Effect, Period of Adoption, Adjustment | Impact of Adoption of Topic 326 on opening balance sheet
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect adjustment to retained earnings	$ 600

Revenues - Revenues By Products

Revenues - Revenues By Products And Service Offerings (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue from contract with customers	$ 166,442	$ 130,837	$ 454,863	$ 359,009
TASER 7
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue from contract with customers	21,702	20,214	48,616	39,466
TASER X26P
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue from contract with customers	9,766	11,578	30,338	37,832
TASER X2
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue from contract with customers	14,494	13,241	45,401	40,413
TASER Pulse
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue from contract with customers	2,981	1,132	6,374	2,920
Cartridges
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue from contract with customers	26,335	18,901	76,732	57,354
Axon Body
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue from contract with customers	15,978	6,763	40,645	18,820
Axon Flex
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue from contract with customers	1,589	1,670	3,452	4,517
Axon Fleet
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue from contract with customers	4,215	4,341	13,088	10,977
Axon Dock
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue from contract with customers	5,708	3,358	14,714	9,401
Axon Evidence and cloud services
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue from contract with customers	46,142	34,240	128,271	93,824
Extended warranties
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue from contract with customers	11,779	9,257	33,047	27,405
Other
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue from contract with customers	5,753	6,142	14,185	16,080
TASER
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue from contract with customers	84,406	71,743	230,791	197,706
TASER | TASER 7
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue from contract with customers	21,702	20,214	48,616	39,466
TASER | TASER X26P
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue from contract with customers	9,766	11,578	30,338	37,832
TASER | TASER X2
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue from contract with customers	14,494	13,241	45,401	40,413
TASER | TASER Pulse
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue from contract with customers	2,981	1,132	6,374	2,920
TASER | Cartridges
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue from contract with customers	26,335	18,901	76,732	57,354
TASER | Axon Body
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue from contract with customers	0	0
TASER | Axon Flex
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue from contract with customers	0	0
TASER | Axon Fleet
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue from contract with customers	0	0
TASER | Axon Dock
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue from contract with customers	0	0
TASER | Axon Evidence and cloud services
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue from contract with customers	692	218	1,776	363
TASER | Extended warranties
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue from contract with customers	5,265	4,543	15,340	13,341
TASER | Other
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue from contract with customers	3,171	1,916	6,214	6,017
Software and Sensors
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue from contract with customers	82,036	59,094	224,072	161,303
Software and Sensors | TASER 7
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue from contract with customers	0	0
Software and Sensors | TASER X26P
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue from contract with customers	0	0
Software and Sensors | TASER X2
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue from contract with customers	0	0
Software and Sensors | TASER Pulse
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue from contract with customers	0	0
Software and Sensors | Cartridges
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue from contract with customers	0	0
Software and Sensors | Axon Body
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue from contract with customers	15,978	6,763	40,645	18,820
Software and Sensors | Axon Flex
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue from contract with customers	1,589	1,670	3,452	4,517
Software and Sensors | Axon Fleet
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue from contract with customers	4,215	4,341	13,088	10,977
Software and Sensors | Axon Dock
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue from contract with customers	5,708	3,358	14,714	9,401
Software and Sensors | Axon Evidence and cloud services
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue from contract with customers	45,450	34,022	126,495	93,461
Software and Sensors | Extended warranties
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue from contract with customers	6,514	4,714	17,707	14,064
Software and Sensors | Other
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue from contract with customers	$ 2,582	$ 4,226	$ 7,971	$ 10,063

Revenues - Revenues By Geograph

Revenues - Revenues By Geographic Area (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Disaggregation of Revenue [Line Items]
Revenue from contract with customers	$ 166,442	$ 130,837	$ 454,863	$ 359,009
United States
Disaggregation of Revenue [Line Items]
Revenue from contract with customers	143,380	110,809	368,390	298,736
Other countries
Disaggregation of Revenue [Line Items]
Revenue from contract with customers	$ 23,062	$ 20,028	$ 86,473	$ 60,273
Revenue from Contract with Customer | Geographic Concentration Risk
Disaggregation of Revenue [Line Items]
Concentration risk, percentage	100.00%	100.00%	100.00%	100.00%
Revenue from Contract with Customer | Geographic Concentration Risk | United States
Disaggregation of Revenue [Line Items]
Concentration risk, percentage	86.00%	85.00%	81.00%	83.00%
Revenue from Contract with Customer | Geographic Concentration Risk | Other countries
Disaggregation of Revenue [Line Items]
Concentration risk, percentage	14.00%	15.00%	19.00%	17.00%

Revenues - Contract Assets, Con

Revenues - Contract Assets, Contract Liabilities (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Revenue from Contract with Customer [Abstract]
Contract assets, net	$ 78,124
Contract liabilities (deferred revenue)	242,464	$ 205,800
Revenue recognized in the period from:
Amounts included in contract liabilities at the beginning of the period	$ 113,422

Revenues - Schedule Of Contract

Revenues - Schedule Of Contract Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Disaggregation of Revenue [Line Items]
Current	$ 154,731	$ 117,864
Long-Term	87,733	87,936
Total	242,464	205,800
TASER
Disaggregation of Revenue [Line Items]
Current	29,610	22,578
Long-Term	28,039	32,611
Total	57,649	55,189
Software and Sensors
Disaggregation of Revenue [Line Items]
Current	125,121	95,286
Long-Term	59,694	55,325
Total	184,815	150,611
Warranty
Disaggregation of Revenue [Line Items]
Current	25,595	22,568
Long-Term	18,807	21,534
Total	44,402	44,102
Warranty | TASER
Disaggregation of Revenue [Line Items]
Current	13,267	12,716
Long-Term	14,824	16,378
Total	28,091	29,094
Warranty | Software and Sensors
Disaggregation of Revenue [Line Items]
Current	12,328	9,852
Long-Term	3,983	5,156
Total	16,311	15,008
Hardware
Disaggregation of Revenue [Line Items]
Current	42,846	31,804
Long-Term	52,567	49,227
Total	95,413	81,031
Hardware | TASER
Disaggregation of Revenue [Line Items]
Current	15,621	9,569
Long-Term	12,124	15,468
Total	27,745	25,037
Hardware | Software and Sensors
Disaggregation of Revenue [Line Items]
Current	27,225	22,235
Long-Term	40,443	33,759
Total	67,668	55,994
Software and Sensors
Disaggregation of Revenue [Line Items]
Current	86,290	63,492
Long-Term	16,359	17,175
Total	102,649	80,667
Software and Sensors | TASER
Disaggregation of Revenue [Line Items]
Current	722	293
Long-Term	1,091	765
Total	1,813	1,058
Software and Sensors | Software and Sensors
Disaggregation of Revenue [Line Items]
Current	85,568	63,199
Long-Term	15,268	16,410
Total	$ 100,836	$ 79,609

Revenues - Revenue Performance

Revenues - Revenue Performance Obligations (Details) $ in Millions	Sep. 30, 2020USD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 1,510
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-10-01 | Minimum
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation to be recognized in the next twelve months, percent	20.00%
Revenue, remaining performance obligation, expected timing of satisfaction, period	5 years
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-10-01 | Maximum
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation to be recognized in the next twelve months, percent	25.00%
Revenue, remaining performance obligation, expected timing of satisfaction, period	12 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2027-10-01 | Maximum
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, expected timing of satisfaction, period	7 years

Cash, Cash Equivalents, and Inv

Cash, Cash Equivalents, and Investments (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Jan. 01, 2020	Dec. 31, 2019
Restricted Cash and Cash Equivalents Items [Line Items]
Amortized Cost	$ 627,698		$ 396,283
Gross Unrealized Gains	606		107
Gross Unrealized Losses	(180)		(34)
Fair Value	628,124		396,356
Cash and Cash Equivalents	176,005		172,250
Short-term investments	331,040		178,534
Long-term Investments	120,653		45,499
Credit loss reserve for held-to-maturity investments	200	$ 100
Level 1
Restricted Cash and Cash Equivalents Items [Line Items]
Amortized Cost	156,693		41,714
Gross Unrealized Gains	144		14
Gross Unrealized Losses	0		(4)
Fair Value	156,837		41,724
Cash and Cash Equivalents	36,797		8,845
Short-term investments	76,395		15,131
Long-term Investments	43,501		17,738
Level 2
Restricted Cash and Cash Equivalents Items [Line Items]
Amortized Cost	379,506		251,250
Gross Unrealized Gains	462		93
Gross Unrealized Losses	(180)		(30)
Fair Value	379,788		251,313
Cash and Cash Equivalents	47,709		60,086
Short-term investments	254,645		163,403
Long-term Investments	77,152		27,761
Cash
Restricted Cash and Cash Equivalents Items [Line Items]
Amortized Cost	91,499		103,319
Gross Unrealized Losses	0		0
Fair Value	91,499		103,319
Cash and Cash Equivalents	91,499		103,319
Short-term investments	0		0
Money market funds | Level 1
Restricted Cash and Cash Equivalents Items [Line Items]
Amortized Cost	31,298		8,845
Gross Unrealized Losses	0		0
Fair Value	31,298		8,845
Cash and Cash Equivalents	31,298		8,845
Short-term investments	0		0
Agency bonds | Level 1
Restricted Cash and Cash Equivalents Items [Line Items]
Amortized Cost	68,111		32,869
Gross Unrealized Gains	141		14
Gross Unrealized Losses	0		(4)
Fair Value	68,252		32,879
Cash and Cash Equivalents	0		0
Short-term investments	24,610		15,131
Long-term Investments	43,501		17,738
Treasury bills | Level 1
Restricted Cash and Cash Equivalents Items [Line Items]
Amortized Cost	57,284
Gross Unrealized Gains	3
Gross Unrealized Losses	0
Fair Value	57,287
Cash and Cash Equivalents	5,499
Short-term investments	51,785
State and municipal obligations | Level 2
Restricted Cash and Cash Equivalents Items [Line Items]
Amortized Cost	63,363		25,038
Gross Unrealized Gains	49		8
Gross Unrealized Losses	(14)		0
Fair Value	63,398		25,046
Cash and Cash Equivalents	1,001		0
Short-term investments	49,441		21,560
Long-term Investments	12,921		3,478
Certificates of Deposit | Level 2
Restricted Cash and Cash Equivalents Items [Line Items]
Amortized Cost	1,900		1,400
Gross Unrealized Losses	0		0
Fair Value	1,900		1,400
Cash and Cash Equivalents	0		0
Short-term investments	1,400		1,400
Long-term Investments	500
Corporate bonds | Level 2
Restricted Cash and Cash Equivalents Items [Line Items]
Amortized Cost	222,817		135,175
Gross Unrealized Gains	389		71
Gross Unrealized Losses	(166)		(30)
Fair Value	223,040		135,216
Cash and Cash Equivalents	2,908		886
Short-term investments	156,178		113,241
Long-term Investments	63,731		21,048
U.S. Treasury repurchase agreements | Level 2
Restricted Cash and Cash Equivalents Items [Line Items]
Amortized Cost	43,800		57,200
Gross Unrealized Losses	0		0
Fair Value	43,800		57,200
Cash and Cash Equivalents	43,800		57,200
Short-term investments	0		0
Treasury inflation - protected securities | Level 2
Restricted Cash and Cash Equivalents Items [Line Items]
Amortized Cost	3,270		3,235
Gross Unrealized Gains	24		14
Gross Unrealized Losses	0		0
Fair Value	3,294		3,249
Cash and Cash Equivalents	0		0
Short-term investments	3,270		0
Long-term Investments			3,235
Commercial Paper | Level 2
Restricted Cash and Cash Equivalents Items [Line Items]
Amortized Cost	44,356		29,202
Gross Unrealized Losses	0		0
Fair Value	44,356		29,202
Cash and Cash Equivalents	0		2,000
Short-term investments	$ 44,356		$ 27,202

Expected Credit Losses (Details

Expected Credit Losses (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2020USD ($)
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance, beginning of period	$ 1,567
Adoption of Topic 326, cumulative-effect adjustment to retained earnings	768
Provision for expected credit losses	693
Amounts written off charged against the allowance	(63)
Other, including dispositions and foreign currency translation	(3)
Balance, end of period	2,962
United States
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance, beginning of period	1,395
Adoption of Topic 326, cumulative-effect adjustment to retained earnings	767
Provision for expected credit losses	578
Amounts written off charged against the allowance	(61)
Balance, end of period	2,679
Other countries
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance, beginning of period	172
Adoption of Topic 326, cumulative-effect adjustment to retained earnings	1
Provision for expected credit losses	115
Amounts written off charged against the allowance	(2)
Other, including dispositions and foreign currency translation	(3)
Balance, end of period	283
COVID-19
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Provision for expected credit losses	$ 800

Expected Credit Losses - Type O

Expected Credit Losses - Type Of Customer Receivable (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Expected Credit Losses
Accounts receivable and notes receivable, current	$ 1,787	$ 1,567
Contract assets, net	711
Long-term notes receivable, net of current portion	464
Total allowance for expected credit losses on customer receivables	$ 2,962

Inventory (Details)

Inventory (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Inventory Disclosure [Abstract]
Inventory, finished goods, trial and evaluation hardware	$ 2,100	$ 1,400
Raw materials	43,082	20,789
Finished goods	54,528	18,056
Total inventory	$ 97,610	$ 38,845

Property and Equipment - Summar

Property and Equipment - Summary of Property and Equipment (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Total cost	$ 147,356	$ 85,602
Less: Accumulated depreciation	(44,638)	(41,832)
Property, Plant and Equipment, Net, Total	102,718	43,770
Land
Property, Plant and Equipment [Line Items]
Total cost	57,052	2,900
Building and leasehold improvements
Property, Plant and Equipment [Line Items]
Total cost	$ 20,330	20,089
Building and leasehold improvements | Minimum
Property, Plant and Equipment [Line Items]
Estimated Useful Life	3 years
Building and leasehold improvements | Maximum
Property, Plant and Equipment [Line Items]
Estimated Useful Life	39 years
Production equipment
Property, Plant and Equipment [Line Items]
Total cost	$ 32,919	29,961
Production equipment | Minimum
Property, Plant and Equipment [Line Items]
Estimated Useful Life	3 years
Production equipment | Maximum
Property, Plant and Equipment [Line Items]
Estimated Useful Life	7 years
Computers, equipment and software
Property, Plant and Equipment [Line Items]
Total cost	$ 7,839	8,126
Computers, equipment and software | Minimum
Property, Plant and Equipment [Line Items]
Estimated Useful Life	3 years
Computers, equipment and software | Maximum
Property, Plant and Equipment [Line Items]
Estimated Useful Life	5 years
Furniture and office equipment
Property, Plant and Equipment [Line Items]
Total cost	$ 6,014	6,514
Furniture and office equipment | Minimum
Property, Plant and Equipment [Line Items]
Estimated Useful Life	5 years
Furniture and office equipment | Maximum
Property, Plant and Equipment [Line Items]
Estimated Useful Life	7 years
Vehicles
Property, Plant and Equipment [Line Items]
Estimated Useful Life	5 years
Total cost	$ 1,782	1,753
Website development costs
Property, Plant and Equipment [Line Items]
Estimated Useful Life	3 years
Total cost	$ 204	204
Capitalized internal-use software development costs
Property, Plant and Equipment [Line Items]
Estimated Useful Life	3 years
Total cost	$ 3,670	3,670
Construction-in-process
Property, Plant and Equipment [Line Items]
Total cost	$ 17,546	$ 12,385

Property and Equipment - Narrat

Property and Equipment - Narrative (Details) - Land $ in Millions	1 Months Ended
	Sep. 30, 2020USD ($)
Property, Plant and Equipment [Line Items]
Purchase price of land	$ 49.1
Land purchased during the year	50.6
Cost incurred under public infrastructure reimbursement development agreement	2.2
Milestone cost to be paid to the company upon achievement of milestones	9.4
Legal and broker fees
Property, Plant and Equipment [Line Items]
Land purchased during the year	$ 1.3

Goodwill and Intangible Asset_2

Goodwill and Intangible Assets - Schedule of Goodwill (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2020USD ($)
Goodwill [Roll Forward]
Balance, beginning of period	$ 25,013
Foreign currency translation adjustments	(1)
Balance, end of period	25,012
TASER
Goodwill [Roll Forward]
Balance, beginning of period	1,354
Balance, end of period	1,354
Software and Sensors
Goodwill [Roll Forward]
Balance, beginning of period	23,659
Foreign currency translation adjustments	(1)
Balance, end of period	$ 23,658

Goodwill and Intangible Asset_3

Goodwill and Intangible Assets - Definite-Lived Intangible Assets Other than Goodwill (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Intangible Assets [Line Items]
Amortizable (definite-lived) intangible assets, Gross Carrying Amount	$ 24,443	$ 24,438
Amortizable (definite-lived) intangible assets, Accumulated Amortization	(15,758)	(13,409)
Total	8,685	11,029
Non-amortizable (indefinite-lived) intangible assets, Carrying Amount	1,575	1,742
Intangible assets, Gross Carrying Amount	26,018	26,180
Intangible assets, Net Carrying Amount	10,260	12,771
TASER trademark
Intangible Assets [Line Items]
Non-amortizable (indefinite-lived) intangible assets, Carrying Amount	900	900
Patents and trademarks pending
Intangible Assets [Line Items]
Non-amortizable (indefinite-lived) intangible assets, Carrying Amount	675	842
Domain names
Intangible Assets [Line Items]
Amortizable (definite-lived) intangible assets, Gross Carrying Amount	3,161	3,161
Amortizable (definite-lived) intangible assets, Accumulated Amortization	(1,263)	(1,035)
Total	$ 1,898	2,126
Domain names | Minimum
Intangible Assets [Line Items]
Amortizable (definite-lived) intangible assets, Useful Life	5 years
Domain names | Maximum
Intangible Assets [Line Items]
Amortizable (definite-lived) intangible assets, Useful Life	10 years
Issued patents
Intangible Assets [Line Items]
Amortizable (definite-lived) intangible assets, Gross Carrying Amount	$ 3,216	3,271
Amortizable (definite-lived) intangible assets, Accumulated Amortization	(1,510)	(1,339)
Total	$ 1,706	1,932
Issued patents | Minimum
Intangible Assets [Line Items]
Amortizable (definite-lived) intangible assets, Useful Life	5 years
Issued patents | Maximum
Intangible Assets [Line Items]
Amortizable (definite-lived) intangible assets, Useful Life	25 years
Issued trademarks
Intangible Assets [Line Items]
Amortizable (definite-lived) intangible assets, Gross Carrying Amount	$ 1,200	1,166
Amortizable (definite-lived) intangible assets, Accumulated Amortization	(573)	(678)
Total	$ 627	488
Issued trademarks | Minimum
Intangible Assets [Line Items]
Amortizable (definite-lived) intangible assets, Useful Life	3 years
Issued trademarks | Maximum
Intangible Assets [Line Items]
Amortizable (definite-lived) intangible assets, Useful Life	15 years
Customer relationships
Intangible Assets [Line Items]
Amortizable (definite-lived) intangible assets, Gross Carrying Amount	$ 3,712	3,721
Amortizable (definite-lived) intangible assets, Accumulated Amortization	(1,784)	(1,416)
Total	$ 1,928	2,305
Customer relationships | Minimum
Intangible Assets [Line Items]
Amortizable (definite-lived) intangible assets, Useful Life	4 years
Customer relationships | Maximum
Intangible Assets [Line Items]
Amortizable (definite-lived) intangible assets, Useful Life	8 years
Non-compete agreements
Intangible Assets [Line Items]
Amortizable (definite-lived) intangible assets, Gross Carrying Amount	$ 452	450
Amortizable (definite-lived) intangible assets, Accumulated Amortization	(419)	(404)
Total	$ 33	46
Non-compete agreements | Minimum
Intangible Assets [Line Items]
Amortizable (definite-lived) intangible assets, Useful Life	3 years
Non-compete agreements | Maximum
Intangible Assets [Line Items]
Amortizable (definite-lived) intangible assets, Useful Life	4 years
Developed technology
Intangible Assets [Line Items]
Amortizable (definite-lived) intangible assets, Gross Carrying Amount	$ 10,660	10,660
Amortizable (definite-lived) intangible assets, Accumulated Amortization	(8,167)	(6,528)
Total	$ 2,493	4,132
Developed technology | Minimum
Intangible Assets [Line Items]
Amortizable (definite-lived) intangible assets, Useful Life	3 years
Developed technology | Maximum
Intangible Assets [Line Items]
Amortizable (definite-lived) intangible assets, Useful Life	5 years
Re-acquired distribution rights
Intangible Assets [Line Items]
Amortizable (definite-lived) intangible assets, Useful Life	2 years
Amortizable (definite-lived) intangible assets, Gross Carrying Amount	$ 2,042	2,009
Amortizable (definite-lived) intangible assets, Accumulated Amortization	(2,042)	$ (2,009)
Total	$ 0

Goodwill and Intangible Asset_4

Goodwill and Intangible Assets Goodwill and Intangible Assets - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Amortization expense of intangible assets	$ 0.8	$ 0.8	$ 2.5	$ 2.7

Goodwill and Intangible asset_5

Goodwill and Intangible assets - Estimated Amortization Expense of Intangible Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
2020 remaining	$ 831
2021	2,879
2022	1,277
2023	982
2024	899
2025	632
Thereafter	1,185
Total	$ 8,685	$ 11,029

Other Long-Term Assets (Details

Other Long-Term Assets (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Oct. 31, 2020	Mar. 31, 2020	Dec. 31, 2019
Schedule of Investments [Line Items]
Cash surrender value of corporate-owned life insurance policies	$ 4,225			$ 4,214
Deferred commissions	27,263			22,068
Restricted cash	59			56
Operating lease assets	22,368			9,653
Investment in unconsolidated affiliate	4,700		$ 4,700
Investment, impairment recorded	0
Warrants for unconsolidated affiliate	2,588
Prepaid expenses, deposits and other	6,085			4,190
Total other long-term assets	$ 67,288			$ 40,181
Flock Group Inc.
Schedule of Investments [Line Items]
Equity method investment, ownership percentage			5.00%
Subsequent Event
Schedule of Investments [Line Items]
Investment in unconsolidated affiliate		$ 2,100
Subsequent Event | Flock Group Inc.
Schedule of Investments [Line Items]
Equity method investment, ownership percentage		4.00%

Accrued Liabilities (Details)

Accrued Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019	Sep. 30, 2019	Dec. 31, 2018
Payables and Accruals [Abstract]
Accrued salaries, benefits and bonus	$ 25,365	$ 24,737
Accrued professional, consulting and lobbying fees	11,483	3,235
Accrued warranty expense	745	1,476	$ 1,071	$ 898
Accrued income and other taxes	18,086	3,362
Accrued inventory in transit	10,185	4,156
Other accrued expenses	8,250	8,035
Accrued liabilities	$ 74,114	$ 45,001

Income Taxes (Details)

Income Taxes (Details) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2020USD ($)	Sep. 30, 2020USD ($)
Tax Credit Carryforward [Line Items]
Deferred tax assets, net	$ 39.2	$ 39.2
Unrecognized tax benefits	7	7
Research and development tax credit studies		$ 2.8
Overall effective tax rate, after discrete period adjustments (as a percentage)		(79.80%)
Effective tax rate, before discrete period adjustment (as a percentage)		(137.00%)
Restricted Stock Units (RSUs)
Tax Credit Carryforward [Line Items]
Discrete tax benefit, stock-based compensation		$ 6.6
United Kingdom
Tax Credit Carryforward [Line Items]
Release of valuation allowance	1.3
Canada
Tax Credit Carryforward [Line Items]
Release of valuation allowance	0.3
State Tax
Tax Credit Carryforward [Line Items]
Unrecognized tax benefits recognized during period	$ 7	$ 7

Stockholders' Equity - Follow-o

Stockholders' Equity - Follow-on Offering (Details) - Common Stock $ / shares in Units, $ in Millions	1 Months Ended	3 Months Ended
	Jun. 30, 2020USD ($)$ / sharesshares	Jun. 30, 2020$ / sharesshares
Class of Stock [Line Items]
Common stock sold (in shares) | shares	3,450,000	3,450,000
Offering price | $ / shares	$ 92	$ 92
Gross proceeds from public offering | $	$ 317.4
Net proceeds from public offering | $	$ 306.8
Underwriters' option to purchase additional shares
Class of Stock [Line Items]
Common stock sold (in shares) | shares	450,000

Stockholders' Equity - CEO Perf

Stockholders' Equity - CEO Performance Award - Additional Information (Details) $ in Thousands	May 24, 2018USD ($)trancheitemshares	Sep. 30, 2020USD ($)shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
First tranche	$ 2,500,000
Tranche incremental increase	$ 1,000,000
Revenue goal number 1		$ 710,058
Revenue goal number 2		860,058
Revenue goal number 3		1,010,058
Revenue goal number 4		1,210,058
Revenue goal number 5		1,410,058
Revenue goal number 6		1,610,058
Revenue goal number 7		1,810,058
Revenue goal number 8		2,010,058
Adjusted EBITDA goal number 9		125,000
Adjusted EBITDA goal number 10		155,000
Adjusted EBITDA goal number 11		175,000
Adjusted EBITDA goal number 12		190,000
Adjusted EBITDA goal number 13		200,000
Adjusted EBITDA goal number 14		210,000
Adjusted EBITDA goal number 15		220,000
Adjusted EBITDA goal number 16		230,000
Recorded share-based compensation expense		$ 69,500
Number of options expected to vest | shares		5,800,000
Chief Executive Officer
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of vesting tranches | tranche	12
Vesting period	10 years
Number of performance goals, revenue | item	8
Number of performance goals, adjusted EBITDA | item	8
Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance shares authorized (in shares) | shares	6,365,856
Unrecognized share-based compensation cost related to unvested stock option awards, probable of achievement		$ 158,900
Weighted average period over which costs are recognized		5 years 1 month 2 days
Unrecognized share-based compensation cost related to unvested stock option awards, not probable of achievement		$ 17,600

Stockholders' Equity - eXponent

Stockholders' Equity - eXponential Stock Performance Plan (Details) $ in Millions	Feb. 12, 2019USD ($)trancheitem	May 24, 2018USD ($)shares	Sep. 30, 2020USD ($)shares	Sep. 30, 2020USD ($)shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
First tranche		$ 2,500
Tranche incremental increase		$ 1,000
Recorded share-based compensation expense				$ 69.5
Number of options expected to vest | shares			5,800,000	5,800,000
Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance shares authorized (in shares) | shares		6,365,856
Unrecognized share-based compensation cost related to unvested stock option awards, probable of achievement			$ 158.9	$ 158.9
Weighted average period over which costs are recognized				5 years 1 month 2 days
Unrecognized share-based compensation cost related to unvested stock option awards, not probable of achievement			$ 17.6	$ 17.6
2019 eXponential Stock Performance Plan | eXponential Stock Units (XSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock, expiration period	9 years
Performance shares authorized (in shares) | shares			100,000	300,000
Number of vesting tranches | tranche	12
First tranche	$ 2,500
Number of performance goals, revenue | item	8
Number of performance goals, adjusted EBITDA | item	8
Tranche incremental increase	$ 1,000
Anti-dilution provision, maximum shares growth rate per year				3.00%
Recorded share-based compensation expense				$ 42
Number of options expected to vest | shares			5,000,000	5,000,000
2019 eXponential Stock Performance Plan | Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized share-based compensation cost related to unvested stock option awards, probable of achievement			$ 139.9	$ 139.9
Weighted average period over which costs are recognized				4 years 10 months 28 days
Unrecognized share-based compensation cost related to unvested stock option awards, not probable of achievement			$ 11.4	$ 11.4

Stockholders' Equity - Summary

Stockholders' Equity - Summary of RSU and PSU Activity (Details) $ / shares in Units, shares in Thousands, $ in Thousands	9 Months Ended
	Sep. 30, 2020USD ($)$ / sharesshares
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding [Roll Forward]
Number of Units outstanding, beginning of year (in shares) | shares	1,249
Number of Units, Granted (in shares) | shares	279
Number of Units, Released (in shares) | shares	(394)
Number of Units, Forfeited (in shares) | shares	(85)
Number of Units outstanding, end of period (in shares) | shares	1,049
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Weighted Average Grant Date Fair Value, Units outstanding, beginning of year (in dollars per share) | $ / shares	$ 45.47
Weighted Average Grant Date Fair Value, Granted (in dollars per share) | $ / shares	78.86
Weighted Average Grant Date Fair Value, Released (in dollars per share) | $ / shares	39
Weighted Average Grant Date Fair Value, Forfeited (in dollars per share) | $ / shares	50.82
Weighted Average Grant Date Fair Value, Units outstanding, end of period (in dollars per share) | $ / shares	$ 56.34
Aggregate intrinsic value at end of period | $	$ 95,112
Performance Stock Units (PSUs)
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding [Roll Forward]
Number of Units outstanding, beginning of year (in shares) | shares	6,033
Number of Units, Granted (in shares) | shares	380
Number of Units, Released (in shares) | shares	(160)
Number of Units, Forfeited (in shares) | shares	(474)
Number of Units outstanding, end of period (in shares) | shares	5,779
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Weighted Average Grant Date Fair Value, Units outstanding, beginning of year (in dollars per share) | $ / shares	$ 34.47
Weighted Average Grant Date Fair Value, Granted (in dollars per share) | $ / shares	55.94
Weighted Average Grant Date Fair Value, Released (in dollars per share) | $ / shares	25.20
Weighted Average Grant Date Fair Value, Forfeited (in dollars per share) | $ / shares	43.09
Weighted Average Grant Date Fair Value, Units outstanding, end of period (in dollars per share) | $ / shares	$ 35.43
Aggregate intrinsic value at end of period | $	$ 524,180

Stockholders' Equity - RSU and

Stockholders' Equity - RSU and PSU - Additional Information (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Nov. 03, 2020	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Tax payments, for net share settlement of share based award	$ 6,886	$ 3,268
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate intrinsic value price per share (in dollars per share)	$ 90.70
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate intrinsic value price per share (in dollars per share)	$ 90.70
Unrecognized stock-based compensation expense related to non-vested stock options	$ 41,700
Weighted average period over which costs are recognized	1 year 11 months 26 days
Number of units, granted (in shares)	279
Number of units outstanding (in shares)	1,049			1,249
Shares withheld, for net share settlement of share based award (in shares)	13
Tax payments, for net share settlement of share based award	$ 1,100
Performance Stock Units (PSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate intrinsic value price per share (in dollars per share)	$ 90.70
Unrecognized stock-based compensation expense related to non-vested stock options	$ 143,900
Weighted average period over which costs are recognized	4 years 9 months 25 days
Number of units, granted (in shares)	380
Performance criteria had been met (in shares)	100
Number of units outstanding (in shares)	5,779			6,033
Maximum additional shares to be issued (in shares)	200
Shares withheld, for net share settlement of share based award (in shares)	1
Tax payments, for net share settlement of share based award	$ 100
Performance Stock Units (PSUs) | Subsequent Event
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized stock-based compensation expense related to non-vested stock options			$ 3,500
Minimum | Performance Stock Units (PSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of targeted shares vested	0.00%
Maximum | Performance Stock Units (PSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of targeted shares vested	200.00%

Stockholders' Equity - Summar_2

Stockholders' Equity - Summary of the Company's Stock Options Activity (Details) - Stock Options - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	9 Months Ended
	Sep. 30, 2020
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Number of options, Options outstanding, beginning of year (in shares)	6,431
Number of options, Granted (in shares)	0
Number of options, Exercised (in shares)	(65)
Number of options, Expired / terminated (in shares)	0
Number of options, Options outstanding, end of year (in shares)	6,366
Number of options, Options exercisable, end of period (in shares)	1
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Weighted average exercise price, Options outstanding, beginning of year (in dollars per share)	$ 28.34
Weighted average exercise price, Granted (in dollars per share)	0
Weighted average exercise price, Exercised (in dollars per share)	4.52
Weighted average exercise price, Expired / terminated (in dollars per share)	0
Weighted average exercise price, Options outstanding, end of period (in dollars per share)	28.58
Weighted average exercise price, Options exercisable, end of period (in dollars per share)	$ 4.70
Weighted average remaining contractual life, Options outstanding, end of period	7 years 4 months 28 days
Weighted average remaining contractual life, Options exercisable, end of period	3 months 3 days
Aggregate intrinsic value, Options outstanding, end of period	$ 395,449
Aggregate intrinsic value, Options exercisable, end of period	$ 2

Stockholders' Equity - Stock Op

Stockholders' Equity - Stock Option Activity - Additional Information (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate intrinsic value price per share (in dollars per share)	$ 90.70
Total intrinsic value of options exercised	$ 5.1	$ 1.1
Number of options outstanding (in shares)	6,366		6,431
Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options outstanding (in shares)	6,400
Options related to tranches considered probable of achievement	5,800
Options related to tranches not considered probable of achievement	500

Stockholders' Equity - Reported

Stockholders' Equity - Reported Share-Based Compensation (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 26,094	$ 13,663	$ 80,124	$ 30,195
Cost of products sold and services delivered
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	744	312	2,170	775
Sales, general and administrative expenses
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	19,117	9,508	60,853	19,130
Research and development expenses
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 6,233	$ 3,843	$ 17,101	$ 10,290

Stockholders' Equity - Stock Re

Stockholders' Equity - Stock Repurchase Plan - Additional Information (Details) - USD ($)	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Feb. 28, 2019	Feb. 29, 2016
2019 Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for issuance (in shares)			6,000,000
Shares available for grant under the plan (in shares)	2,000,000
2016 Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding common stock repurchase program authorized amount (up to)				$ 50,000,000
Shares repurchased during period (in shares)	0	0
Remaining authorized repurchase amount	$ 16,300,000

Line of Credit (Details)

Line of Credit (Details)	9 Months Ended
	Sep. 30, 2020USD ($)	Dec. 31, 2019USD ($)
Debt Instrument [Line Items]
Maximum ratio of total liabilities to tangible net worth	2.50
Line of Credit
Debt Instrument [Line Items]
Available borrowing under letter of credit	$ 43,900,000
Line of credit facility, increase (decrease), net	100,000,000
Line of credit borrowings	0	$ 0
Letters of credit outstanding amount	$ 6,100,000
Company's leverage ratio	0
Unsecured Revolving Line of Credit | Line of Credit
Debt Instrument [Line Items]
Total availability under line of credit agreement	$ 50,000,000
Letter of Credit | Line of Credit
Debt Instrument [Line Items]
Available borrowing under letter of credit	$ 10,000,000
Minimum | London Interbank Offered Rate (LIBOR) | Line of Credit
Debt Instrument [Line Items]
Debt instrument basis spread on variable rate	1.00%
Maximum | London Interbank Offered Rate (LIBOR) | Line of Credit
Debt Instrument [Line Items]
Debt instrument basis spread on variable rate	1.50%

Commitments and Contingencies (

Commitments and Contingencies (Details) $ in Millions	Sep. 30, 2020USD ($)lawsuit
Loss Contingencies [Line Items]
Number of lawsuits against Company | lawsuit	12
Self insurance on product claim	$ 5
Pending dismissal
Loss Contingencies [Line Items]
Number of lawsuits against Company | lawsuit	2
Surety Bond
Loss Contingencies [Line Items]
Bonds outstanding	$ 24
Expiring in 2020 | Surety Bond
Loss Contingencies [Line Items]
Bonds outstanding	0.1
Expiring in 2021 | Surety Bond
Loss Contingencies [Line Items]
Bonds outstanding	2.7
Expiring in 2022 | Surety Bond
Loss Contingencies [Line Items]
Bonds outstanding	3.2
Expiring in 2023 | Surety Bond
Loss Contingencies [Line Items]
Bonds outstanding	7.5
Expiring in 2024 | Surety Bond
Loss Contingencies [Line Items]
Bonds outstanding	10.5
Line of Credit
Loss Contingencies [Line Items]
Letters of credit outstanding amount	6.1
Outstanding letters of credit and bank guarantees not drawn against credit facility	$ 2

Employee Benefit Plans (Details

Employee Benefit Plans (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Defined Benefit Plan Disclosure [Line Items]
Employee deferrals deemed vested percentage upon contribution			100.00%
Defined contribution plan, cost	$ 1.3	$ 0.9	$ 4.1	$ 3.5
Maximum
Defined Benefit Plan Disclosure [Line Items]
Deferral percentage of base salary (up to)			80.00%
Deferral percentage of other compensation (up to)			100.00%

Segment Data (Details)

Segment Data (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020USD ($)	Sep. 30, 2019USD ($)	Sep. 30, 2020USD ($)segment	Sep. 30, 2019USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments of company | segment			2
Net sales	$ 166,442	$ 130,837	$ 454,863	$ 359,009
Cost of sales	68,202	50,668	179,838	144,363
Gross margin	98,240	80,169	275,025	214,646
Research and development	29,246	25,129	85,187	71,976
TASER
Segment Reporting Information [Line Items]
Net sales	84,406	71,743	230,791	197,706
Cost of sales	31,297	26,504	88,787	74,044
Gross margin	53,109	45,239	142,004	123,662
Research and development	3,355	3,485	10,149	10,284
Software and Sensors
Segment Reporting Information [Line Items]
Net sales	82,036	59,094	224,072	161,303
Cost of sales	36,905	24,164	91,051	70,319
Gross margin	45,131	34,930	133,021	90,984
Research and development	25,891	21,644	75,038	61,692
Product
Segment Reporting Information [Line Items]
Net sales	120,091	96,497	326,134	264,977
Cost of sales	57,798	42,445	150,507	120,265
Product | TASER
Segment Reporting Information [Line Items]
Net sales	83,517	71,424	228,569	197,148
Cost of sales	31,297	26,504	88,787	74,044
Product | Software and Sensors
Segment Reporting Information [Line Items]
Net sales	36,574	25,073	97,565	67,829
Cost of sales	26,501	15,941	61,720	46,221
Service
Segment Reporting Information [Line Items]
Net sales	46,351	34,340	128,729	94,032
Cost of sales	10,404	8,223	29,331	24,098
Service | TASER
Segment Reporting Information [Line Items]
Net sales	889	319	2,222	558
Cost of sales	0	0
Service | Software and Sensors
Segment Reporting Information [Line Items]
Net sales	45,462	34,021	126,507	93,474
Cost of sales	$ 10,404	$ 8,223	$ 29,331	$ 24,098