Organization and Summary of Significant Accounting Policies (Condensed) (Details)	3 Months Ended
	Mar. 31, 2016 USD ($) Test country $ / shares shares	Mar. 31, 2015 USD ($)	Dec. 31, 2015 USD ($)
Revenue Recognition
Minimum number of Oncotype DX tests by exclusive distribution agreements | Test	1
Minimum number of countries covered for distribution agreements establishment | country	90
Accrued refunds	$ 501,000		$ 609,000
Allowance for Doubtful Accounts
Allowance for doubtful accounts	3,996,000		$ 3,988,000
Write-offs for doubtful accounts recorded against allowance	2,400,000	$ 1,000,000
Bad debt expense	2,300,000	$ 1,000,000
Investments in Equity Securities
Proceeds from sales of marketable securities	3,579,000
Realized gains on available-for-sale marketable securities	1,333,000
Amount reclassified out of accumulated other comprehensive income	442,000
Amount reclassified out of accumulated other comprehensive income, tax portion	251,000
Invitae
Investments in Equity Securities
Available-for-sale marketable security	$ 18,900,000
Common Stock | Sale | Invitae
Investments in Equity Securities
Number of shares of cost method investment sold by entity | shares	357,883
Proceeds from sales of marketable securities	$ 3,600,000
Sale price of cost method investment (in dollars per share) | $ / shares	$ 6.28
Realized gains on available-for-sale marketable securities	$ 1,300,000
Available-for-sale marketable security	11,600,000
Amount reclassified out of accumulated other comprehensive income	442,000
Amount reclassified out of accumulated other comprehensive income, tax portion	$ 251,000