Income Taxes - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Income Taxes [Line Items]
Provision for income taxes	$ (599,000)	$ 3,900,000	$ (1,201,000)
Operating loss carryforwards	136,600,000
Federal and state research and development credits available for carryforward	10,400,000
Loss carryforwards range, expiration year	2033
Research and development credit carryforwards range, expiration year	2033
Capital loss carryforwards	284,600,000
Uncertain tax positions	1,846,000	1,875,000	1,732,000	1,687,000
Canada [Member]
Income Taxes [Line Items]
Provision for income taxes	(599,000)	4,205,000	(1,421,000)
Operating loss carryforwards	102,900,000
U.S. Subsidiaries [Member]
Income Taxes [Line Items]
Operating loss carryforwards	33,700,000
Federal and state research and development credits available for carryforward	$ 1,300,000