FAIR VALUE MEASUREMENTS - Narrative (Details)		1 Months Ended		12 Months Ended		36 Months Ended
	Sep. 14, 2018 USD ($)	Feb. 28, 2021 USD ($)	Apr. 30, 2020 USD ($)	Mar. 31, 2020 USD ($) company	Mar. 31, 2019 USD ($)	Mar. 31, 2021 company	Feb. 05, 2020 USD ($)	Apr. 03, 2019 USD ($)	Sep. 30, 2018 USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Number of companies acquired | company				2		2
Fair value of contingent liability				$ 1,748,000
Fair value, measurements, recurring | Contingent consideration
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liability adjustment included in earnings				36,000
Disposal Group, Disposed of by Sale, Not Discontinued Operations | Handheld Network Test Tools Business
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent consideration related to the divestiture	$ 2,300,000				$ 2,300,000				$ 2,300,000
Contingent consideration measurement period	2 years				2 years
Change in fair value of contingent consideration				800,000	$ 1,600,000
Maximum | Disposal Group, Disposed of by Sale, Not Discontinued Operations | Handheld Network Test Tools Business
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent consideration related to the divestiture	$ 4,000,000.0				$ 4,000,000.0
Gigavation
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of contingent liability				700,000			$ 800,000
Payments of contingent consideration		$ 700,000
Eastwind
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of contingent liability				$ 1,000,000.0				$ 1,000,000
Payments of contingent consideration			$ 1,000,000.0