Organization and Summary of Significant Accounting Policies, Unrealized Loss Position (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Net realized gains (losses) related to available-for-sale securities	$ 0	$ 0
Continuous unrealized loss position, fair value [Abstract]
In loss position less than 12 months	16,352	22,388
In loss position more than 12 months	6,765	14,447
Total in loss position	23,117	36,835
Continuous unrealized loss position, unrealized losses [Abstract]
In loss position less than 12 months	(16)	(25)
In loss position more than 12 months	(25)	(66)
Total in loss position	(41)	(91)
Certificates of Deposit [Member]
Continuous unrealized loss position, fair value [Abstract]
In loss position less than 12 months	480	1,439
In loss position more than 12 months	0	240
Total in loss position	480	1,679
Continuous unrealized loss position, unrealized losses [Abstract]
In loss position less than 12 months	0	(1)
In loss position more than 12 months	0	0
Total in loss position	0	(1)
Corporate Notes and Bonds [Member]
Continuous unrealized loss position, fair value [Abstract]
In loss position less than 12 months	12,450	20,949
In loss position more than 12 months	5,767	11,218
Total in loss position	18,217	32,167
Continuous unrealized loss position, unrealized losses [Abstract]
In loss position less than 12 months	(15)	(24)
In loss position more than 12 months	(25)	(59)
Total in loss position	(40)	(83)
U.S. Government Agency Securities [Member]
Continuous unrealized loss position, fair value [Abstract]
In loss position less than 12 months	3,422	0
In loss position more than 12 months	998	2,989
Total in loss position	4,420	2,989
Continuous unrealized loss position, unrealized losses [Abstract]
In loss position less than 12 months	(1)	0
In loss position more than 12 months	0	(7)
Total in loss position	$ (1)	$ (7)