Contingencies (Details Textual) (USD $) In Millions, unless otherwise specified	3 Months Ended		12 Months Ended
	Mar. 31, 2012	Apr. 02, 2011	Dec. 31, 2011	Feb. 11, 2011	Feb. 08, 2011
Contingencies (Textual) [Abstract]
Agreed consideration for securities litigation settlement				$ 38.0
Payment to securities litigation settlement fund			16.4
Company portion of the securities litigation settlement consideration			15.8
Company portion of accrued interest for securities litigation settlement			0.6
Consideration for securities litigation settlement paid by Company's insurers	22.2
Consideration for proposed securities litigation settlement to be paid by Cadence's insurers				22.2
Plaintiff's attorneys fees to be paid by Cadence's insurers as part of derivative settlement					1.8
Warranty on sale of hardware products to customers	generally for a 90-day period
Significant losses from indemnification claims	$ 0	$ 0
General period of warranty on sales of hardware products	90 days