Annual report pursuant to Section 13 and 15(d)

Summary of Significant Accounting Policies - Schedule of Fair Value of Financial Instruments (Details)

v3.19.1
Summary of Significant Accounting Policies - Schedule of Fair Value of Financial Instruments (Details) - USD ($)
$ in Thousands
Dec. 31, 2018
Dec. 31, 2017
Fair Value of Marketable Securities $ 6,687 $ 18,765
Level 1 [Member]    
Fair Value of Marketable Securities
Level 2 [Member]    
Fair Value of Marketable Securities 6,687 18,765
Level 3 [Member]    
Fair Value of Marketable Securities
U.S. Government Obligations [Member]    
Fair Value of Marketable Securities 2,398 1,744
U.S. Government Obligations [Member] | Level 1 [Member]    
Fair Value of Marketable Securities
U.S. Government Obligations [Member] | Level 2 [Member]    
Fair Value of Marketable Securities 2,398 1,744
U.S. Government Obligations [Member] | Level 3 [Member]    
Fair Value of Marketable Securities
Corporate Obligations [Member]    
Fair Value of Marketable Securities 4,289 17,021
Corporate Obligations [Member] | Level 1 [Member]    
Fair Value of Marketable Securities
Corporate Obligations [Member] | Level 2 [Member]    
Fair Value of Marketable Securities 4,289 17,021
Corporate Obligations [Member] | Level 3 [Member]    
Fair Value of Marketable Securities