Commitments and Contingencies (Details) € in Millions								3 Months Ended			9 Months Ended
	May. 21, 2015	Apr. 02, 2015	Mar. 23, 2015 EUR (€)	Mar. 23, 2015 USD ($)	Sep. 16, 2013 USD ($)	Apr. 27, 2012 USD ($)	May. 05, 2010 defendant	Sep. 30, 2015 USD ($)	Jun. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)	Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)	Dec. 31, 2014 USD ($)
Loss Contingencies [Line Items]
Number of defendants | defendant							4
Probable or reasonably possible loss								$ 0			$ 0
Operating leases, expiration date											2023
Operating leases, future minimum payments due								6,200,000			$ 6,200,000
Operating leases, future minimum, sublease receipts								1,600,000			1,600,000
Rent expense								500,000		$ 500,000	1,700,000	$ 1,600,000
Penalty payment derivative								400,000			400,000		$ 500,000
Proceeds from public stock offering, net of offering costs						$ 39,800,000
Revenue								83,560,000		$ 81,576,000	250,316,000	$ 227,195,000
Securities lock up agreement period	180 days	60 days
Additional paid-in capital								507,969,000			507,969,000		$ 456,189,000
PendingLitigationMember
Loss Contingencies [Line Items]
Partial settlement of claims					$ 492,000
Accrual for estimated net litigation expense			€ 1	$ 1,100,000				0	$ 0
Embedded Derivative Financial Instruments [Member]
Loss Contingencies [Line Items]
Other non-current liability								5,000,000			5,000,000
RUSSIAN FEDERATION
Loss Contingencies [Line Items]
Exit fees											3,500,000
Exit fees for future											1,500,000
Indemnification Guarantee [Member]
Loss Contingencies [Line Items]
Probable or reasonably possible loss								0			0
Private Placement [Member] | Embedded Derivative Financial Instruments [Member]
Loss Contingencies [Line Items]
Penalty payment derivative								100,000			100,000
Additional paid-in capital								4,900,000			4,900,000
Private Placement [Member] | Performance Guarantee [Member]
Loss Contingencies [Line Items]
Other non-current liability								$ 30,000,000			$ 30,000,000