Acquisitions Details (Details) - USD ($)				1 Months Ended	3 Months Ended			12 Months Ended
	Jul. 06, 2021	Mar. 26, 2021	Dec. 13, 2019	Apr. 30, 2020	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2019	Sep. 30, 2019	Dec. 31, 2018	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Jan. 22, 2018	Nov. 01, 2016
Business Acquisition [Line Items]
Change in fair value of contingent consideration								$ 5,772,000	$ (128,000)		$ 1,190,000
Operating lease right-of-use assets								15,684,000	14,334,000
Operating lease liabilities								18,368,000	16,193,000
Goodwill								225,522,000	210,135,000		153,422,000
Opengear
Business Acquisition [Line Items]
Cash paid at closing			$ 148,058,000
Weighted average useful life identifiable intangibles			13 years 4 months 24 days
Goodwill			$ 57,088,000
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Intangibles								800,000
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Financial Assets								(1,100,000)
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Financial Liabilities								300,000
Opengear | General and Administrative
Business Acquisition [Line Items]
Acquisition costs								300,000	2,700,000		300,000
Haxiot
Business Acquisition [Line Items]
Cash paid at closing		$ 7,100,000
Cash acquired		50,000
Goodwill		$ 8,605,000
Haxiot | General and Administrative
Business Acquisition [Line Items]
Acquisition costs								$ 300,000
Ctek
Business Acquisition [Line Items]
Cash paid at closing	$ 12,012,000
Goodwill	$ 4,867,000
Ctek | General and Administrative
Business Acquisition [Line Items]
Acquisition costs					$ 300,000
Maximum
Business Acquisition [Line Items]
Useful life identifiable intangibles								14 years 6 months
Earn-out payments | Opengear | 2019
Business Acquisition [Line Items]
Earn-out payment maximum										$ 5,000,000
Earn-out payments | Opengear | 2020
Business Acquisition [Line Items]
Earn-out payment maximum																$ 10,000,000
Earn-out payments | Forecast | Haxiot | 2021
Business Acquisition [Line Items]
Earn-out payment maximum															$ 3,000,000
Business Combination, Contingent Consideration, Liability															0
Earn-out payments | Forecast | Haxiot | 2022
Business Acquisition [Line Items]
Earn-out payment maximum														$ 5,000,000
Business Combination, Contingent Consideration, Liability														5,900,000
Earn-out payments | Forecast | Ctek | 2021
Business Acquisition [Line Items]
Earn-out payment maximum															$ 500,000
Earn-out payments | Forecast | Ctek | 2022
Business Acquisition [Line Items]
Earn-out payment maximum														$ 1,000,000
Earn-out payments | Forecast | Ctek | 2023
Business Acquisition [Line Items]
Earn-out payment maximum													$ 1,500,000
Customer Relationships | Opengear
Business Acquisition [Line Items]
Useful life identifiable intangibles			14 years 6 months
Purchased and Core Technology | Opengear
Business Acquisition [Line Items]
Useful life identifiable intangibles			9 years
Trademarks | Opengear
Business Acquisition [Line Items]
Useful life identifiable intangibles			12 years
Other non-current assets | Opengear
Business Acquisition [Line Items]
Operating lease right-of-use assets			$ 1,400,000
Other current liabilities and other non-current liabilities | Opengear
Business Acquisition [Line Items]
Operating lease liabilities			$ 1,700,000
Contingent Consideration | Opengear
Business Acquisition [Line Items]
Change in fair value of contingent consideration						$ 10,000,000	$ 900,000
Contingent Consideration | Accelerated Concepts
Business Acquisition [Line Items]
Change in fair value of contingent consideration				$ 2,400,000							$ 3,500,000
Contingent Consideration | TempAlert
Business Acquisition [Line Items]
Change in fair value of contingent consideration										$ 0		$ 0
Estimate of Fair Value Measurement | Fair Value, Measurements, Recurring | Contingent Consideration
Business Acquisition [Line Items]
Contingent consideration fair value								$ 6,200,000	$ 4,228,000
Estimate of Fair Value Measurement | Fair Value, Measurements, Recurring | Contingent Consideration | Accelerated Concepts
Business Acquisition [Line Items]
Contingent consideration fair value																	$ 2,300,000
Estimate of Fair Value Measurement | Fair Value, Measurements, Recurring | Contingent Consideration | TempAlert
Business Acquisition [Line Items]
Contingent consideration fair value																		$ 0