Organization and Summary of Significant Accounting Policies, Fair Value Disclosures (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Fair value hierarchy for financial assets measured at fair value [Abstract]
Fair value for financial assets	$ 53,409	$ 65,734
Recurring [Member] | Cash Equivalents and Short-Term Investments [Member]
Fair value hierarchy for financial assets measured at fair value [Abstract]
Fair value for financial assets	45,816	57,248
Recurring [Member] | Cash Equivalents and Short-Term Investments [Member] | Level 1 [Member]
Fair value hierarchy for financial assets measured at fair value [Abstract]
Fair value for financial assets	9,297	19,112
Recurring [Member] | Cash Equivalents and Short-Term Investments [Member] | Level 2 [Member]
Fair value hierarchy for financial assets measured at fair value [Abstract]
Fair value for financial assets	36,519	38,136
Recurring [Member] | Cash Equivalents and Short-Term Investments [Member] | Level 3 [Member]
Fair value hierarchy for financial assets measured at fair value [Abstract]
Fair value for financial assets	0	0
Recurring [Member] | Cash Equivalents and Short-Term Investments [Member] | Money Market Funds [Member]
Fair value hierarchy for financial assets measured at fair value [Abstract]
Fair value for financial assets	9,297	19,112
Recurring [Member] | Cash Equivalents and Short-Term Investments [Member] | Money Market Funds [Member] | Level 1 [Member]
Fair value hierarchy for financial assets measured at fair value [Abstract]
Fair value for financial assets	9,297	19,112
Recurring [Member] | Cash Equivalents and Short-Term Investments [Member] | Money Market Funds [Member] | Level 2 [Member]
Fair value hierarchy for financial assets measured at fair value [Abstract]
Fair value for financial assets	0	0
Recurring [Member] | Cash Equivalents and Short-Term Investments [Member] | Money Market Funds [Member] | Level 3 [Member]
Fair value hierarchy for financial assets measured at fair value [Abstract]
Fair value for financial assets	0	0
Recurring [Member] | Cash Equivalents and Short-Term Investments [Member] | Certificates of Deposit [Member]
Fair value hierarchy for financial assets measured at fair value [Abstract]
Fair value for financial assets	1,273	2,979
Recurring [Member] | Cash Equivalents and Short-Term Investments [Member] | Certificates of Deposit [Member] | Level 1 [Member]
Fair value hierarchy for financial assets measured at fair value [Abstract]
Fair value for financial assets	0	0
Recurring [Member] | Cash Equivalents and Short-Term Investments [Member] | Certificates of Deposit [Member] | Level 2 [Member]
Fair value hierarchy for financial assets measured at fair value [Abstract]
Fair value for financial assets	1,273	2,979
Recurring [Member] | Cash Equivalents and Short-Term Investments [Member] | Certificates of Deposit [Member] | Level 3 [Member]
Fair value hierarchy for financial assets measured at fair value [Abstract]
Fair value for financial assets	0	0
Recurring [Member] | Cash Equivalents and Short-Term Investments [Member] | Commercial Paper [Member]
Fair value hierarchy for financial assets measured at fair value [Abstract]
Fair value for financial assets	4,989	996
Recurring [Member] | Cash Equivalents and Short-Term Investments [Member] | Commercial Paper [Member] | Level 1 [Member]
Fair value hierarchy for financial assets measured at fair value [Abstract]
Fair value for financial assets	0	0
Recurring [Member] | Cash Equivalents and Short-Term Investments [Member] | Commercial Paper [Member] | Level 2 [Member]
Fair value hierarchy for financial assets measured at fair value [Abstract]
Fair value for financial assets	4,989	996
Recurring [Member] | Cash Equivalents and Short-Term Investments [Member] | Commercial Paper [Member] | Level 3 [Member]
Fair value hierarchy for financial assets measured at fair value [Abstract]
Fair value for financial assets	0	0
Recurring [Member] | Cash Equivalents and Short-Term Investments [Member] | Corporate Notes and Bonds [Member]
Fair value hierarchy for financial assets measured at fair value [Abstract]
Fair value for financial assets	19,317	31,172
Recurring [Member] | Cash Equivalents and Short-Term Investments [Member] | Corporate Notes and Bonds [Member] | Level 1 [Member]
Fair value hierarchy for financial assets measured at fair value [Abstract]
Fair value for financial assets	0	0
Recurring [Member] | Cash Equivalents and Short-Term Investments [Member] | Corporate Notes and Bonds [Member] | Level 2 [Member]
Fair value hierarchy for financial assets measured at fair value [Abstract]
Fair value for financial assets	19,317	31,172
Recurring [Member] | Cash Equivalents and Short-Term Investments [Member] | Corporate Notes and Bonds [Member] | Level 3 [Member]
Fair value hierarchy for financial assets measured at fair value [Abstract]
Fair value for financial assets	0	0
Recurring [Member] | Cash Equivalents and Short-Term Investments [Member] | U.S. Government Agency Securities [Member]
Fair value hierarchy for financial assets measured at fair value [Abstract]
Fair value for financial assets	10,940	2,989
Recurring [Member] | Cash Equivalents and Short-Term Investments [Member] | U.S. Government Agency Securities [Member] | Level 1 [Member]
Fair value hierarchy for financial assets measured at fair value [Abstract]
Fair value for financial assets	0	0
Recurring [Member] | Cash Equivalents and Short-Term Investments [Member] | U.S. Government Agency Securities [Member] | Level 2 [Member]
Fair value hierarchy for financial assets measured at fair value [Abstract]
Fair value for financial assets	10,940	2,989
Recurring [Member] | Cash Equivalents and Short-Term Investments [Member] | U.S. Government Agency Securities [Member] | Level 3 [Member]
Fair value hierarchy for financial assets measured at fair value [Abstract]
Fair value for financial assets	$ 0	$ 0