Consolidated Statements of Stockholders' Equity (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2015	Dec. 31, 2014
Statement Of Stockholders Equity [Abstract]
Sale of stock for common stock and pre funded warrants, offering costs		$ 2,095
Sale of stock for Common stock, offering costs	$ 142

Pre funded warrants and stock issued during period value offering costs.

No definition available.

Name:	mstx_PreFundedWarrantsAndStockIssuedDuringPeriodValueOfferingCosts
Namespace Prefix:	mstx_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration