XML 70 R59.htm IDEA: XBRL DOCUMENT v2.4.1.9

Product Milestone Payments and Royalty Agreements - Additional Information (Detail) (USD $)	12 Months Ended	36 Months Ended	1 Months Ended
	Dec. 31, 2014	Dec. 31, 2014	Jun. 30, 2005
Royalty Agreement [Line Items]
Additional consideration of asset purchase agreement			10,950,000mgnx_AdditionalPaymentUponAchievementOfMilestone
Common stock shares			36,135mgnx_NumberOfPotentialSharesToBeIssuedAsAdditionalConsiderationUnderAssetPurchaseAgreement
Payments related to the additional considerations		0mgnx_AmountOfAdditionalConsiderationPaidUnderAgreement
Revenue from product sales	$ 0us-gaap_SalesRevenueGoodsNet
Minimum [Member]
Royalty Agreement [Line Items]
Maximum royalty payments percentage			1.75%mgnx_RoyaltyPaymentAsPercentageOfNetSalesUnderLicensingAgreement / us-gaap_RangeAxis = us-gaap_MinimumMember
Maximum [Member]
Royalty Agreement [Line Items]
Maximum royalty payments percentage			4.00%mgnx_RoyaltyPaymentAsPercentageOfNetSalesUnderLicensingAgreement / us-gaap_RangeAxis = us-gaap_MaximumMember

X

- Definition

Additional payment upon achievement of milestone.

+ References

No definition available.

+ Details

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Namespace Prefix:	mgnx_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Definition

Amount of additional consideration paid under agreement.

+ References

No definition available.

+ Details

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Namespace Prefix:	mgnx_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- Definition

Number of potential shares to be issued as additional consideration under asset purchase agreement.

+ References

No definition available.

+ Details

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Namespace Prefix:	mgnx_
Data Type:	xbrli:sharesItemType
Balance Type:	na
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X

- Details

Name:	mgnx_RoyaltyAgreementLineItems
Namespace Prefix:	mgnx_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Royalty payment as percentage of net sales under licensing agreement.

+ References

No definition available.

+ Details

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Namespace Prefix:	mgnx_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Aggregate revenue during the period from the sale of goods in the normal course of business, after deducting returns, allowances and discounts.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.1(a))

-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688



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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 1

-Article 5

+ Details

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Data Type:	xbrli:monetaryItemType
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Period Type:	duration

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- Details

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- Details

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