Commitment and Contingencies (Details) (USD $)	0 Months Ended		3 Months Ended
	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014 item	Sep. 30, 2011
Commitments and Contingencies.
Letter of credit with Silicon Valley Bank				$ 525,000
Accounts receivable. | Credit risk | Customers
Customer Concentration
Number of customers	4	4
Concentration risk (as a percent)	62.20%	69.90%
Accounts receivable. | Credit risk | Customer one
Customer Concentration
Concentration risk (as a percent)	30.80%	30.20%
Accounts receivable. | Credit risk | Customer two
Customer Concentration
Concentration risk (as a percent)	14.40%	16.00%
Accounts receivable. | Credit risk | Customer three
Customer Concentration
Concentration risk (as a percent)	10.30%	13.40%
Accounts receivable. | Credit risk | Customer four
Customer Concentration
Concentration risk (as a percent)	6.70%	10.30%
Revenues. | Credit risk | Customers
Customer Concentration
Number of customers	1		2
Concentration risk (as a percent)	63.50%		31.60%
Revenues. | Credit risk | Customer one
Customer Concentration
Concentration risk (as a percent)			21.10%
Revenues. | Credit risk | Customer two
Customer Concentration
Concentration risk (as a percent)			10.50%