Note 15 - Overdraft Facility and Working Capital Line of Credit - Revolving Line of Credit (Details) $ in Thousands, £ in Millions		3 Months Ended
		Mar. 31, 2019 USD ($)	Mar. 31, 2019 GBP (£)	Dec. 31, 2018 USD ($)
General Intangibles [Member] | CUI, Inc [Member]
CUI Inc. and CUI-Canada General intangibles, net		$ 8,337
Accounts Receivable [Member] | CUI, Inc [Member]
CUI Inc. and CUI-Canada General intangibles, net		8,773
Inventory [Member] | CUI, Inc [Member]
CUI Inc. and CUI-Canada General intangibles, net		9,791
Equipment [Member] | CUI, Inc [Member]
CUI Inc. and CUI-Canada General intangibles, net		654
Multi-currency Variable Rate Overdraft Facility [Member]
Line of credit facility		965
Multi-currency Variable Rate Overdraft Facility [Member] | Wells Fargo Bank [Member]
Line of credit facility, maximum borrowing capacity		1,953	£ 1.5
Line of credit facility		$ 965
Line of credit facility, expiration date		Oct. 05, 2021
Line of credit facility, interest rate		2.50%	2.50%
Multi-currency Variable Rate Overdraft Facility [Member] | Wells Fargo Bank [Member] | Base Rate [Member]
Line of credit facility, variable interest rate		2.25%
Revolving Credit Facility [Member]
Line of credit facility		$ 1,460
Revolving Credit Facility [Member] | Wells Fargo Bank [Member]
Line of credit facility, maximum borrowing capacity	[1]	5,000
Line of credit facility	[2]	$ 1,460
Line of credit facility, expiration date		Jun. 01, 2019
Line of credit facility, interest rate		2.25%	2.25%
Revolving Credit Facility [Member] | Wells Fargo Bank [Member] | London Interbank Offered Rate (LIBOR) [Member]
Line of credit facility, variable interest rate		2.25%

[1] $2 million of the line of credit is reserved to guarantee the obligation of Orbital Gas Systems Ltd. under its Overdraft Facility.

[2] As a result of the Company's cash management system, checks issued but not presented to the bank for payment may create negative book cash balances. When those checks are presented for payment if there isn't sufficient cash in the bank account, the checks would be honored by the bank with a corresponding increase to CUI's draw on its line of credit. There were no negative book cash balances included in the balance on the line of credit as of March 31, 2019.