BASIS OF PRESENTATION (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2013
BASIS OF PRESENTATION
Unrestricted cash, cash equivalents and investments	$ 37,709
Minimum period for which unrestricted cash, cash equivalents and investments and cash to be generated from existing grants and expected product sales will be sufficient to meet projected operating requirements	12 months

Represents the minimum period for which unrestricted cash, cash equivalents and investments and cash to be generated from expected product sales will be sufficient to meet projected operating requirements.

No definition available.

Name:	mblx_MinimumPeriodForWhichCashCashEquivalentsInvestmentsAndCashFromExpectedProductSalesIsSufficientToMeetProjectedOperatingRequirements
Namespace Prefix:	mblx_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration