Organization and Summary of Significant Accounting Policies (Details) (USD $)	3 Months Ended		9 Months Ended			3 Months Ended		1 Months Ended					9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012 item	Sep. 30, 2011	Dec. 31, 2011	Jun. 30, 2012 Private company 1, Cost Method Investment	Sep. 30, 2012 Private company 1, Cost Method Investment	Aug. 31, 2012 Private company 2	Sep. 30, 2012 Private company 2	Dec. 31, 2011 Private company 2	Mar. 31, 2011 Private company 2	Dec. 31, 2010 Private company 1, Equity Method Investment	Sep. 30, 2012 Genomic Health International Holdings, LLC item
Organization and summary of significant accounting policies
Number of wholly-owned subsidiaries			3										3
Revenue Recognition
Minimum number of Oncotype DX tests by exclusive distribution agreements			1
Accrued refunds	$ 541,000		$ 541,000		$ 562,000
Allowance for Doubtful Accounts
Allowance for doubtful accounts	1,171,000		1,171,000		1,206,000
Write-offs for doubtful accounts recorded against allowance	972,000	797,000	2,600,000	2,300,000
Bad debt expense	998,000	939,000	2,600,000	2,500,000
Investments in Privately Held Companies
Amount invested in preferred stock of a private company												500,000
Investments in privately held companies	3,900,000		3,900,000		2,600,000
Percentage of ownership interest in private company												21.00%
Additional investment made in preferred stock of a private company						400,000		1,000,000
Percentage of ownership interest in private company accounted for under the cost method of accounting						16.00%		19.00%
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%
Carrying value of investment in the redeemable preferred stock of a private company										2,300,000
Net carrying value of investment							$ 643,000		$ 3,300,000