Summary of Significant Accounting Policies - Concentration of Credit Risk (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2015 USD ($) customer	Dec. 31, 2014 USD ($) customer	Dec. 31, 2013 USD ($) customer	Dec. 31, 2012 USD ($)
Revenue, Major Customer [Line Items]
Cash and cash equivalents | $	$ 7,114	$ 7,908	$ 6,509	$ 5,219
Foreign Countries
Revenue, Major Customer [Line Items]
Cash and cash equivalents | $	$ 200	$ 2,500
Sales Revenue, Net | Customer Concentration Risk
Revenue, Major Customer [Line Items]
Number of customers | customer	3	3	3
Concentration risk, percentage	47.00%
Accounts Receivable | Customer Concentration Risk
Revenue, Major Customer [Line Items]
Number of customers | customer	2	2
Customer One | Sales Revenue, Net | Customer Concentration Risk
Revenue, Major Customer [Line Items]
Concentration risk, percentage	18.00%	15.00%	16.00%
Customer One | Accounts Receivable | Customer Concentration Risk
Revenue, Major Customer [Line Items]
Concentration risk, percentage	19.00%	23.00%
Customer Two | Sales Revenue, Net | Customer Concentration Risk
Revenue, Major Customer [Line Items]
Concentration risk, percentage	15.00%	15.00%	15.00%
Customer Two | Accounts Receivable | Customer Concentration Risk
Revenue, Major Customer [Line Items]
Concentration risk, percentage	24.00%	20.00%
Customer Three | Sales Revenue, Net | Customer Concentration Risk
Revenue, Major Customer [Line Items]
Concentration risk, percentage	14.00%	15.00%	14.00%