Restructuring Expenses - Additional Information (Details) (USD $)	3 Months Ended	12 Months Ended	27 Months Ended
	Mar. 31, 2015 Lease	Dec. 31, 2013 Employee	Mar. 31, 2015	May 22, 2014	Aug. 18, 2014	Dec. 31, 2014
Sub-lease 1 \| Facility Closing
Restructuring Cost And Reserve [Line Items]
Restructuring reserve balance				$ 900,000
Sub Lease 2 \| Facility Closing
Restructuring Cost And Reserve [Line Items]
Restructuring reserve balance					700,000
Property Subject to Operating Lease
Restructuring Cost And Reserve [Line Items]
Restructuring reserve balance	1,195,000		1,195,000			1,282,000
Number of sub leases	2
Operating Expense [Member]
Restructuring Cost And Reserve [Line Items]
Number of positions eliminated		59
Severance costs			5,500,000
Accrued Expenses [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring reserve balance	900,000		900,000
Accrued Expenses [Member] \| Sub Lease 2
Restructuring Cost And Reserve [Line Items]
Restructuring reserve balance	200,000		200,000
Other Noncurrent Liabilities
Restructuring Cost And Reserve [Line Items]
Restructuring reserve balance	$ 1,000,000		$ 1,000,000