Accounts receivable: (Tables)

12 Months Ended

Dec. 31, 2012

Accounts receivable:

Schedule of accounts receivable

	December 31, 2012			December 31, 2011
Customer trade receivable	$	39,754		$	43,181
Government funding receivable	541			582
Due from joint venture (note 21)	2,127			416
Other receivables	1,916			7,528
Income taxes receivable	172			—
Allowance for doubtful accounts	(321		)	(785		)
	$	44,189		$	50,922