Summary of Significant Accounting Policies - Investments (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2012
Accounting Policies [Abstract]
Other-than-temporary impairment charges	$ 0	$ 1,143	$ 0
Gross unrealized loss	420	48
Gross unrealized gains	3,455	8,082
Impairment charge on non-marketable strategic investments	0	2,250	1,000
Impairment loss (gain) on strategic investments, net	0	2,250	(7,147)
Purchases of strategic investments	$ 0	$ (500)	$ (4,750)

Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax

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- Definition

Impairment Loss (Gain) on Strategic Investments, Net

+ References

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- Definition

Amount of unrealized loss on securities classified as available-for-sale.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 50

-Paragraph 6

-Subparagraph (a)(2)

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- Definition

This item represents an other than temporary decline in value that has been recognized against an investment accounted for under the cost method of accounting. The excess of the carrying amount over the fair value of the investment represents the amount of the write down which is or was reflected in earnings. The written down value is a new cost basis with the adjusted value of the investment becoming its new carrying value. Evidence of a loss in value might include, but would not necessarily be limited to, absence of an ability to recover the carrying amount of the investment or inability of the investee to sustain an earnings capacity which would justify the carrying amount of the investment.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 325

-SubTopic 20

-Section 50

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- Definition

The amount by which the fair value of an investment is less than the amortized cost basis or carrying amount of that investment at the balance sheet date and the decline in fair value is deemed to be other than temporary, before considering whether or not such amount is recognized in earnings or other comprehensive income.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (b)

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- Definition

The cash outflow associated with other investments held by the entity for investment purposes not otherwise defined in the taxonomy.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Investing Activities

-URI http://asc.fasb.org/extlink&oid=6516133

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-Topic 230

-SubTopic 10

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-Paragraph 13

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