Significant Accounting Policies (Tables)
3 Months Ended
Mar. 31, 2015
Accounting Policies [Abstract]  
Schedule of Product Warranty Liability [Table Text Block]
Changes in the warranty reserve during the three months ended March 31, 2015 were as follows:
 
 
 
Three Months Ended
 
 
 
March 31, 2015
 
 
 
(in thousands)
 
Balance at beginning of the period
 
$
7,381
 
Provision
 
 
11
 
Utilization
 
 
(806)
 
Balance at end of the period
 
$
6,586