Warranty liability: (Tables)

12 Months Ended

Dec. 31, 2012

Warranty liability:

Schedule of warranty liability

	December 31, 2012			December 31, 2011			March 31, 2011
Balance, beginning of period	$	4,401		$	1,314		$	1,769
Warranty claims	(3,099		)	(1,395		)	(2,124		)
Warranty accruals	5,303			4,530			1,740
Impact of foreign exchange	(225		)	(48		)	(71		)
Balance, end of period	$	6,380		$	4,401		$	1,314
Current portion	(2,072		)	(1,187		)	(154		)
Long-term portion	4,308			3,214			1,160