Note 8 - Related-party Transactions - Transactions Between the Company and Affiliates (Details) - USD ($) $ in Thousands		Jun. 30, 2023	Dec. 31, 2022
Due to affiliates		$ 3,079	$ 2,964
Loans Due to Affiliates [Member] | Local Investors in China [Member]
Due to affiliates	[1]	1,554
Loans Due to Affiliates [Member] | Local Investors in Mexico [Member]
Due to affiliates		623	623
Loans Due to Affiliates [Member] | Local Investors in Australia [Member]
Due to affiliates		636	693
Loans Due to Affiliates [Member] | Local Investors Related to Resource Plus [Member]
Due to affiliates		$ 266	266
Loans Due from Affiliates [Member] | Local Investors in China [Member]
Due to affiliates	[1]		$ 1,382

[1] Represent loans due from the local investors into the Company's subsidiaries (representing their proportionate share of working capital loans). The loans have no payment terms, are due on demand, and are classified as current liabilities in the unaudited condensed consolidated balance sheets