Organization and Summary of Significant Accounting Policies (Details 2) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Fair value in gain/loss position, less than 12 months	$ 14,593	$ 12,740
Unrealized gain (loss), less than 12 months	6	14
Fair value in gain/loss position, more than 12 months	3,195	4,714
Unrealized gain (loss), more than 12 months	(2)	(5)
Fair value in gain/loss position, total	17,788	17,454
Unrealized gain (loss), total	3	9
Certificates of Deposit
Fair value in gain/loss position, less than 12 months	492	475
Unrealized gain (loss), less than 12 months	0	0
Fair value in gain/loss position, more than 12 months	0	0
Unrealized gain (loss), more than 12 months	0	0
Fair value in gain/loss position, total	492	475
Unrealized gain (loss), total	0	0
Corporate Notes and Bonds
Fair value in gain/loss position, less than 12 months	9,502	10,120
Unrealized gain (loss), less than 12 months	5	15
Fair value in gain/loss position, more than 12 months	3,195	4,714
Unrealized gain (loss), more than 12 months	(2)	(5)
Fair value in gain/loss position, total	12,697	14,834
Unrealized gain (loss), total	3	10
U.S. Government Agency Securities
Fair value in gain/loss position, less than 12 months	4,599	2,145
Unrealized gain (loss), less than 12 months	0	(1)
Fair value in gain/loss position, more than 12 months	0	0
Unrealized gain (loss), more than 12 months	0	0
Fair value in gain/loss position, total	4,599	2,145
Unrealized gain (loss), total	$ 0	$ (1)