Industry Risk and Concentration - Additional Information (Detail)	6 Months Ended
Jun. 30, 2012
Concentration Risk [Line Items]
Number of genetic risk assessment tests introduced commercially	4
Amway Global
Concentration Risk [Line Items]
Percentage of sales revenue	63.00%

Percentage of revenue generated from a single external customer that accounts for 10 percent or more of an entity's revenues.

No definition available.

Name:	us-gaap_EntityWideRevenueMajorCustomerPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration