Assets and Liabilities Measured at Fair Value (Details) (USD $)	3 Months Ended		1 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Nov. 30, 2013	Dec. 31, 2014	Dec. 31, 2013
Assets and Liabilities Measured at Fair Value
Transfer of assets from Level 1 to Level 2	$ 0
Transfer of assets from Level 2 to Level 1	0
Contingent consideration payable
Change in fair value	1,000,000	505,000
Assets:
Cash/money market funds	28,827,000	27,533,000		24,074,000	43,640,000
Liabilities:
Contingent consideration payable	11,700,000			10,700,000
Callidus
Contingent consideration payable
Change in fair value	1,000,000
Liabilities:
Contingent consideration payable	11,700,000		10,600,000
Discount rate (as a percent)	11.00%		11.00%
Minimum | Callidus
Contingent consideration payable
Milestone achievement probability (as a percent)	24
Milestone payment	0
Maximum
Contingent consideration payable
Unrealized gain (loss) on securities	1,000
Maximum | Callidus
Contingent consideration payable
Milestone achievement probability (as a percent)	75
Milestone payment	81,000,000
Level 1
Assets:
Fair value of assets	28,827,000			24,074,000
Level 1 | Cash/money market funds
Assets:
Cash/money market funds	28,827,000			24,074,000
Level 2
Assets:
Fair value of assets	123,142,000			145,065,000
Deferred Compensation Plan Assets	398,000
Liabilities:
Deferred Compensation Plan Liability	406,000			124,000
Fair value of liabilities	406,000			124,000
Level 2 | Corporate debt securities
Assets:
Fair value of assets	109,895,000			133,216,000
Level 2 | Commercial paper
Assets:
Fair value of assets	12,499,000			11,499,000
Level 2 | Certificate of deposit
Assets:
Fair value of assets	350,000			350,000
Level 3
Financial assets and liabilities subject to fair value measurements
Contingent success fee payable	370,000			341,000
Liabilities:
Contingent success fee payable	370,000			341,000
Contingent consideration payable	11,700,000			10,700,000
Fair value of liabilities	12,070,000			11,041,000
Total
Financial assets and liabilities subject to fair value measurements
Contingent success fee payable	370,000			341,000
Assets:
Fair value of assets	151,969,000			169,139,000
Deferred Compensation Plan Assets	398,000
Liabilities:
Contingent success fee payable	370,000			341,000
Contingent consideration payable	11,700,000			10,700,000
Deferred Compensation Plan Liability	406,000			124,000
Fair value of liabilities	12,476,000			11,165,000
Total | Cash/money market funds
Assets:
Cash/money market funds	28,827,000			24,074,000
Total | Corporate debt securities
Assets:
Fair value of assets	109,895,000			133,216,000
Total | Commercial paper
Assets:
Fair value of assets	12,499,000			11,499,000
Total | Certificate of deposit
Assets:
Fair value of assets	350,000			350,000
2013 Loan Agreement
Financial assets and liabilities subject to fair value measurements
Fair value of contingent payment	300,000
Period of trigger event within which success fee is payable	6 months
Period of effectiveness of trigger event from closing of loan	5 years
2013 Loan Agreement | Level 3 | Maximum
Financial assets and liabilities subject to fair value measurements
Contingent success fee payable	400,000
Liabilities:
Contingent success fee payable	$ 400,000