INCOME TAXES - Additional Information (Details) - USD ($)		3 Months Ended		12 Months Ended
	Oct. 30, 2018	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019	Dec. 31, 2018
Income Taxes [Line Items]
Effective income tax rate expense, percent		18.60%	16.00%
Income tax expense (benefit)		$ 8,700,000	$ 5,999,000
Long-term asset		$ 89,335,000		$ 86,090,000
Withholding and interest for licencing and royalty payments	$ 13,200,000
Withholding and interest for licencing and royalty payments period	3 years
State and foreign income tax returns subject to examination period minimum (in years)		3 years
State and foreign income tax returns subject to examination period maximum (in years)		4 years
Reduction of Korean Withholding Taxes [Member]
Income Taxes [Line Items]
Reduction of deferred tax asset for foreign tax credits and R&D		$ 20,700,000		20,700,000
U.S.Federal Government [Member]
Income Taxes [Line Items]
Estimated settlement amounts due (refunds) from withholding taxes					$ 16,200,000
Korean Government [Member]
Income Taxes [Line Items]
Estimated settlement amounts due (refunds) from withholding taxes					$ (36,900,000)
Allocation of Withholding to Non-Korean Patents [Member]
Income Taxes [Line Items]
Long-term asset		30,200,000		26,900,000
Allocation of Withholding to Non-Korean Patents [Member] | U.S.Federal Government [Member]
Income Taxes [Line Items]
Estimated settlement amounts due (refunds) from withholding taxes		29,000,000.0		$ 25,700,000
ASU No. 2016-09 [Member]
Income Taxes [Line Items]
Income tax expense (benefit)		$ 450,000	$ 1,500,000