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Restructuring - Additional Information (Detail)
$ / qtr in Millions, $ in Millions
3 Months Ended
Dec. 31, 2017
USD ($)
Mar. 31, 2017
USD ($)
$ / qtr
Dec. 31, 2016
USD ($)
$ / qtr
Restructuring Cost and Reserve [Line Items]      
Reductions in company's worldwide workforce   16.00% 30.00%
Reduction of overall cost structure | $ / qtr     2.5
Special charges for restructuring plan | $   $ 0.3 $ 0.3
Non-cash stock based compensation expense | $   $ 0.1  
Restructuring income | $ $ 0.7    
Minimum [Member]      
Restructuring Cost and Reserve [Line Items]      
Reduction of overall cost structure | $ / qtr   0.9  
Maximum [Member]      
Restructuring Cost and Reserve [Line Items]      
Reduction of overall cost structure | $ / qtr   1.0