Organization and Summary of Significant Accounting Policies (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012 item	Jun. 30, 2011	Dec. 31, 2011	Mar. 31, 2011	Dec. 31, 2010
Organization and summary of significant accounting policies
Number of wholly-owned subsidiaries			4
Revenue Recognition
Minimum number of Oncotype DX tests by exclusive distribution agreements			1
Number of distributors for exclusive distribution agreements			20
Number of countries covered for distribution agreements establishment			80
Accrued refunds	$ 564,000		$ 564,000		$ 562,000
Allowance for Doubtful Accounts
Allowance for doubtful accounts	1,145,000		1,145,000		1,206,000
Write-offs for doubtful accounts recorded against allowance	706,000	714,000	1,600,000	1,500,000
Bad debt expense	884,000	736,000	1,600,000	1,600,000
Investments in Privately Held Companies
Amount invested in preferred stock of a private company							500,000
Investments in privately held companies	2,900,000		2,900,000		2,600,000
Percentage of ownership interest in private company							21.00%
Additional investment made in preferred stock of a private company	400,000
Percentage of ownership interest in private company accounted for under the cost method of accounting	16.00%		16.00%
Net carrying value of investment	637,000		637,000
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%
Carrying value of investment in the redeemable preferred stock of a private company	$ 2,300,000		$ 2,300,000		$ 2,300,000
Genomic Health International Holdings, LLC
Organization and summary of significant accounting policies
Number of wholly-owned subsidiaries			3