Employee Benefit Plans - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Pension Plans, Defined Benefit | Sweden
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Defined contribution plan, company contribution	$ 493,000	$ 457,000	$ 532,000
Minimum
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Defined contribution plan, eligible age of employees	21
Defined Contribution 401 K Plan
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Defined contribution plan, company contribution	$ 107,000	$ 92,000	$ 103,000