Collaboration and Commercial Technology Licensing Agreements (Details)	1 Months Ended	3 Months Ended				6 Months Ended
	Jun. 30, 2016 USD ($) item	Jun. 30, 2016 USD ($)	Jun. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Dec. 31, 2013 USD ($)	Jun. 30, 2016 USD ($)	Sep. 30, 2015 USD ($)	Jun. 30, 2015 USD ($)
Specimen transfer agreements
Collaboration payments and costs
Collaboration expense		$ 1,600,000	$ 2,300,000			$ 2,500,000		$ 9,400,000
Technology license agreements
Collaboration payments and costs
Costs recorded under collaborative arrangements		2,500,000	$ 2,300,000			5,100,000	$ 4,500,000
Exclusive license agreement
Collaboration payments and costs
Collaboration expense								$ 5,500,000
Estimated total remaining obligation, including milestone payments						$ 0
Exclusive license agreement | Research and development expense.
Collaboration payments and costs
Up-front payment					$ 9,000,000
Milestone payment				$ 5,500,000
Oncotype DX DCIS clinical study
Collaboration payments and costs
Period from achieving key milestone entity required to make fixed annual payments						1 year
Fixed annual payments
2016	$ 604,000	604,000				$ 604,000
2017	504,000	504,000				504,000
Exclusive distribution rights Epic's AR-V7 liquid biopsy test in United States
Collaboration payments and costs
Obligation upon achievement of certain milestones	4,000,000	4,000,000				4,000,000
Investment in subordinated convertible promissory notes per agreement	$ 7,500,000	7,500,000				7,500,000
Number of milestones needed to be achieved for conversion into preferred stock | item	1
Investment in preferred stock per collaboration agreement	$ 2,500,000	$ 2,500,000				$ 2,500,000
Term of agreement	10 years