Organization and Summary of Significant Accounting Policies, Cash, Cash Equivalents and Investments (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Available-for-sale Securities, Fair Value to Amortized Cost Basis [Abstract]
Amortized Cost	$ 53,450	$ 65,825
Gross Unrealized Gains	1	0
Gross Unrealized Losses	(42)	(91)
Fair Value	53,409	65,734
Short-Term Investments [Member]
Available-for-sale Securities, Fair Value to Amortized Cost Basis [Abstract]
Amortized Cost	36,560	38,227
Gross Unrealized Gains	1	0
Gross Unrealized Losses	(42)	(91)
Fair Value	36,519	38,136
Commercial Paper [Member]
Available-for-sale Securities, Fair Value to Amortized Cost Basis [Abstract]
Amortized Cost	4,989	996
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	4,989	996
Corporate Notes and Bonds [Member]
Available-for-sale Securities, Fair Value to Amortized Cost Basis [Abstract]
Amortized Cost	19,357	31,255
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(40)	(83)
Fair Value	19,317	31,172
U.S. Government Agency Securities [Member]
Available-for-sale Securities, Fair Value to Amortized Cost Basis [Abstract]
Amortized Cost	10,941	2,996
Gross Unrealized Gains	1	0
Gross Unrealized Losses	(2)	(7)
Fair Value	10,940	2,989
Cash and Cash Equivalents [Member]
Available-for-sale Securities, Fair Value to Amortized Cost Basis [Abstract]
Amortized Cost	16,890	27,598
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	16,890	27,598
Cash [Member]
Available-for-sale Securities, Fair Value to Amortized Cost Basis [Abstract]
Amortized Cost	7,593	8,486
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	7,593	8,486
Money Market Fund [Member]
Available-for-sale Securities, Fair Value to Amortized Cost Basis [Abstract]
Amortized Cost	9,297	19,112
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	9,297	19,112
Certificates of Deposit [Member]
Available-for-sale Securities, Fair Value to Amortized Cost Basis [Abstract]
Amortized Cost	1,273	2,980
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	(1)
Fair Value	$ 1,273	$ 2,979

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 25
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=65884222&loc=d3e22054-111558

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 5
-Subparagraph (aa)
-URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27232-111563

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
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-URI http://asc.fasb.org/extlink&oid=66010992&loc=d3e26610-111562

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Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
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Amount before tax of unrealized loss in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.2)
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