Operating Leases, Annual Rent Increase, Percentage

No definition available.

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- Definition

Operating Leases, Area Leased

+ References

No definition available.

+ Details

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Namespace Prefix:	mrtx_
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Balance Type:	na
Period Type:	instant

- Details

Name:	us-gaap_OperatingLeasedAssetsLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of required minimum rental payments for leases having an initial or remaining non-cancelable letter-terms in excess of one year.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 840

-SubTopic 10

-Section 55

-Paragraph 40

-Subparagraph (Note 3)

-URI http://asc.fasb.org/extlink&oid=6584154&loc=d3e38371-112697

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 840

-SubTopic 20

-Section 50

-Paragraph 2

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=6453985&loc=d3e41502-112717

+ Details

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- Details

Name:	us-gaap_OperatingLeasesFutureMinimumPaymentsDueAbstract
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- Definition

Amount of required minimum rental payments maturing in the next fiscal year following the latest fiscal year for operating leases having an initial or remaining non-cancelable letter-terms in excess of one year.

+ References

+ Details

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- Definition

Amount of required minimum rental payments maturing in the forth fiscal year following the latest fiscal year for operating leases having an initial or remaining non-cancelable letter-terms in excess of one year.

+ References

+ Details

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Period Type:	instant

- Definition

Amount of required minimum rental payments maturing in the third fiscal year following the latest fiscal year for operating leases having an initial or remaining non-cancelable letter-terms in excess of one year.

+ References

+ Details

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Period Type:	instant

- Definition

Amount of required minimum rental payments maturing in the second fiscal year following the latest fiscal year for operating leases having an initial or remaining non-cancelable letter-terms in excess of one year.

+ References

+ Details

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- Details

Name:	us-gaap_OperatingLeasesRentExpenseAbstract
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- Definition

This element represents the payments that the lessee is obligated to make or can be required to make in connection with a property under the terms of an agreement classified as an operating lease, excluding contingent rentals and a guarantee by the lessee of the lessor's debt and the lessee's obligation to pay (apart from the rental payments) executory costs such as insurance, maintenance, and taxes.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 840

-SubTopic 20

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6453985&loc=d3e41499-112717

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 840

-SubTopic 10

-Section 55

-Paragraph 40

-Subparagraph (Note 3)

-URI http://asc.fasb.org/extlink&oid=6584154&loc=d3e38371-112697

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 840

-SubTopic 10

-Section 25

-Paragraph 5

-URI http://asc.fasb.org/extlink&oid=7661868&loc=d3e34039-112682

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Rental expense for the reporting period incurred under operating leases, including minimum and any contingent rent expense, net of related sublease income.

+ References

+ Details

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Namespace Prefix:	us-gaap_
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Balance Type:	debit
Period Type:	duration

- Details

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COMMITMENTS AND CONTINGENCIES (Details) (USD $)	12 Months Ended			0 Months Ended
COMMITMENTS AND CONTINGENCIES (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Jun. 24, 2014
Future minimum annual payments
2014	$ 223,000
2016	290,000
2017	303,000
2018	25,000
Total minimum lease payments	841,000
Operating Leases, Rent Expense, Net [Abstract]
Lease expense	400,000us-gaap_OperatingLeasesRentExpenseNet	400,000us-gaap_OperatingLeasesRentExpenseNet	300,000us-gaap_OperatingLeasesRentExpenseNet
Building
Operating Leased Assets [Line Items]
Area of space leased				18,000
Annual rent increase (percent)				3.00%
Building \| Lease Agreement Phase One
Operating Leased Assets [Line Items]
Area of space leased				2,000
Monthly lease rent				5,900
Building \| Lease Agreement Phase Two
Operating Leased Assets [Line Items]
Area of space leased				14,000
Monthly lease rent				14,000
Building \| Lease Agreement Phase Three
Operating Leased Assets [Line Items]
Area of space leased				2,000
Monthly lease rent				$ 4,200