Summary of Significant Accounting Policies - Product Warranty (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Product Liability Contingency [Line Items]
Product warranty accrual	$ 1,269	$ 814
Summary of product warranty activity
Beginning balance	814	933
Charges to expense	1,457	419
Costs incurred	(1,002)	(538)
Ending balance	$ 1,269	$ 814
Minimum
Product Liability Contingency [Line Items]
Limited product warranty period	1 year
Maximum
Product Liability Contingency [Line Items]
Limited product warranty period	4 years