Subsequent Events (Details) (Subsequent events, Life Sciences Tax Incentive Program 2013, USD $) In Millions, unless otherwise specified	1 Months Ended
Apr. 30, 2013 item
Subsequent events \| Life Sciences Tax Incentive Program 2013
Subsequent event
Tax incentive awarded	$ 0.5
State research and development tax credits monetized	$ 0.4
Number of incremental employees pledged to be hired	20
Performance period	5 years

Represents the state research and development tax credits monetized under the tax incentive and credit programs.

No definition available.

Name:	mack_TaxIncentiveProgramStateResearchAndDevelopmentTaxCreditsMonetized
Namespace Prefix:	mack_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration