Restructuring Charges (Details) (USD $)	3 Months Ended					12 Months Ended			3 Months Ended
	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Mar. 31, 2015
Changes in restructuring liability
Severance and related costs	$ 2,300,000	$ 100,000	$ 200,000	$ 400,000	$ 1,800,000	$ 2,621,000	$ 2,334,000	$ 4,169,000
Severance
Restructuring charges
Stock option modification						100,000
Changes in restructuring liability
Balance at the beginning of the period			43,000		659,000	43,000	659,000	171,000
Severance and related costs						2,565,000	2,334,000	4,169,000
Cash payments						(2,127,000)	(2,950,000)	(3,551,000)
Non-cash items								(130,000)
Balance at the end of the period						481,000	43,000	659,000
Severance | Forecast
Changes in restructuring liability
Cash payments									$ (500,000)