Percentage of Revenue by Geographic Area (Detail) (Total Revenue)	9 Months Ended	12 Months Ended
Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012	Mar. 31, 2011
Concentration Risk [Line Items]
Revenues, percentage by country	100.00%	100.00%	100.00%	100.00%
United States
Concentration Risk [Line Items]
Revenues, percentage by country	48.00%	48.00%	46.00%	50.00%
Sweden
Concentration Risk [Line Items]
Revenues, percentage by country	44.00%	45.00%	42.00%	42.00%
Other
Concentration Risk [Line Items]
Revenues, percentage by country	8.00%	7.00%	12.00%	8.00%

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 275

-SubTopic 10

-Section 50

-Paragraph 18

-URI http://asc.fasb.org/extlink&oid=6927468&loc=d3e6351-108592

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 825

-SubTopic 10

-Section 50

-Paragraph 21

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=7491637&loc=d3e13537-108611

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 275

-SubTopic 10

-Section 50

-Paragraph 20

-URI http://asc.fasb.org/extlink&oid=6927468&loc=d3e6404-108592

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 825

-SubTopic 10

-Section 50

-Paragraph 20

-URI http://asc.fasb.org/extlink&oid=7491637&loc=d3e13531-108611

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Data Type:	num:percentItemType
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