PREPAID LICENSING AND ROYALTY FEES (Tables)

12 Months Ended

Dec. 31, 2018

Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Abstract]

Summary of Changes to Prepaid Licensing and Royalty Fees

The following table summarizes changes to our Company’s prepaid licensing and royalty fees:

(in US$ thousands)	2016			2017			2018
Balance at beginning of year	$	239		$	1,020		$	459
Addition		2,581			486			968
Amortization and usage		(416	)		(1,040	)		(747	)
Exchange difference		2			(7	)		(1	)
Impairment charges (Note 6)		(1,386	)		—			(244	)
Balance at end of year	$	1,020		$	459		$	435