Significant Customer and Geographic Information - Revenue by Geographic Region (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended											12 Months Ended
	Mar. 31, 2013		Dec. 31, 2012		Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012		Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2013		Mar. 31, 2012		Mar. 31, 2011
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues by geographic region	$ 56,326	[1],[2]	$ 51,698	[3]	$ 46,324	$ 41,294	$ 48,767	[1],[4]	$ 56,347	$ 64,929	$ 60,844	$ 195,642		$ 230,887		$ 247,710
United States of America
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues by geographic region												79,930	[5]	99,214	[5]	81,113	[5]
Taiwan
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues by geographic region												22,684		20,950		45,489
Hong Kong
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues by geographic region												22,044		21,458		24,747
China
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues by geographic region												2,053	[5]	4,503	[5]	9,030	[5]
Europe
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues by geographic region												35,216	[5]	41,691	[5]	45,714	[5]
Japan
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues by geographic region												13,237	[5]	13,596	[5]	9,305	[5]
Malaysia
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues by geographic region												4,733	[5]	8,276	[5]	8,258	[5]
Singapore
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues by geographic region												10,399	[5]	14,011	[5]	11,808	[5]
Other Asia
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues by geographic region												4,621		5,790		9,394
Other
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues by geographic region												$ 725		$ 1,398		$ 2,852

[1] During fiscal 2012, one significant product development milestone relating to the Veloce project was considered probable of achievement and accordingly $60.4 million was recognized as research and development expense (see further discussion in Note 4 to the Notes to Consolidated Financial Statements relating to Veloce). However, approximately $8.0 million of the R&D expense was incorrectly recognized as this expense amount related to Unallocated Veloce Units that had not yet been distributed as of March 31, 2012. R&D expenses were also recognized during the first three quarters of fiscal 2013 in connection with further progress made in connection with the performance milestones relating to Veloce. However, the R&D expenses recognized during the first three quarters of fiscal 2013 also incorrectly included immaterial amounts related to the Unallocated Veloce Units. During the fourth quarter of fiscal 2013, the Company corrected the error impacting fiscal 2012 and the first three quarters of fiscal 2013. The correction of the errors resulted in a reduction of R&D expenses recognized by $10.4 million during the fourth quarter of fiscal 2013.

[2] The consolidated operating results for the fourth quarter of fiscal 2013 included a charge of $9.6 million related to the Veloce consideration.

[3] The consolidated operating results for the third quarter of fiscal 2013 included a charge of $51.9 million related to the Veloce consideration and a charge of $6.2 million related to restructuring charges.

[4] The consolidated operating results for the fourth quarter of fiscal 2012 included a charge of $60.4 million related to the Veloce initial consideration and a gain of $8.1 related to the sale of a strategic investment.

[5] Change in revenues was primarily due to shift in customer demand and continuing geographic changes to macro-economic conditions.