4. ALLOWANCE FOR DOUBTFUL ACCOUNTS

Allowance for doubtful accounts are comprised of allowances for accounts receivable trade, advances to suppliers and other receivables.

An analysis of allowances for accounts receivable, trade for the years ended December 31, 2015, 2016 and 2017 is as follows:

	Years Ended December 31,
	2015			2016			2017
	$			$			$
Beginning of the year		31,817			28,156			26,119
Allowances made (reversed) during the year, net		(1,084	)		(854	)		5,345
Accounts written-off against allowances		(858	)		(47	)		(174	)
Foreign exchange effect		(1,719	)		(1,136	)		1,651

Closing balance		28,156			26,119			32,941

An analysis of allowances for advances to suppliers for the years ended December 31, 2015, 2016 and 2017 is as follows:

	Years Ended December 31,
	2015			2016			2017
	$			$			$
Beginning of the year		37,735			28,629			19,527
Allowances made (reversed) during the year, net		1,291			(5,427	)		(833	)
Accounts written-off against allowances		(9,465	)		(3,644	)		—
Foreign exchange effect		(932	)		(31	)		68

Closing balance		28,629			19,527			18,762

An analysis of allowances for other receivables for the years ended December 31, 2015, 2016 and 2017 is as follows:

	Years Ended December 31,
	2015			2016			2017
	$			$			$
Beginning of the year		830			3,885			9,251
Allowances made during the year, net		3,257			5,954			549
Foreign exchange effect		(202	)		(588	)		549

Closing balance		3,885			9,251			10,349