Organization and Summary of Significant Accounting Policies (Details) (USD $)	3 Months Ended		6 Months Ended			1 Months Ended	12 Months Ended		1 Months Ended			6 Months Ended				6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014 subsidiary country test	Jun. 30, 2013	Dec. 31, 2013	Jun. 30, 2012 Private company 1, Cost Method Investment	Dec. 31, 2013 Private company 1, Cost Method Investment	Jun. 30, 2014 Private company 1, Cost Method Investment	Nov. 30, 2013 Private company 2	Oct. 31, 2012 Private company 2	Aug. 31, 2012 Private company 2	Jun. 30, 2014 Private company 2	Dec. 31, 2013 Private company 2	Mar. 31, 2011 Private company 2	Dec. 31, 2010 Private company 1, Equity Method Investment	Jun. 30, 2014 Genomic Health International Holdings, LLC subsidiary
Organization and summary of significant accounting policies
Number of wholly-owned subsidiaries			3													9
Revenue Recognition
Minimum number of Oncotype DX tests by exclusive distribution agreements			1
Minimum number of countries covered for distribution agreements establishment			90
Accrued refunds	$ 1,000,000		$ 1,000,000		$ 770,000
Allowance for Doubtful Accounts
Allowance for doubtful accounts	2,119,000		2,119,000		1,907,000
Write-offs for doubtful accounts recorded against allowance	1,400,000	1,300,000	2,900,000	2,300,000
Bad debt expense	1,600,000	1,600,000	3,200,000	2,900,000
Investments in Privately Held Companies
Amount invested in preferred stock of a private company															500,000
Percentage of ownership interest in private company															21.00%
Additional investment made in preferred stock of a private company						400,000			5,000,000	3,600,000	1,000,000
Percentage of ownership interest in private company accounted for under the cost method of accounting						16.00%				18.00%	19.00%	12.00%	12.00%
Investment in redeemable preferred stock														2,300,000
Investment in the redeemable preferred stock of a private company, percent of the entity's outstanding voting shares														21.00%
Impairment recognized							643,000					0
Carrying value of investments in privately held companies							$ 0	$ 0				$ 11,900,000	$ 11,900,000