Stockholders' Equity (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Jun. 30, 2019	Dec. 31, 2018	May 30, 2019
Stockholders' Equity (Textual)
Reserved common stock shares for issuance	80,030
Common stock reserved for future grants	328,660		49,000
Stock option expenses	$ 414,000
Eighth Amended and Restated Certificate of Incorporation [Member]
Stockholders' Equity (Textual)
Description of preferred stock, authorized		Annual meeting ("2018 Annual Meeting") of stockholders, an amendment to the Company's Eighth Amended and Restated Certificate of Incorporation (as amended, the "Certificate of Incorporation") was approved to decrease the Company's authorized number of shares of preferred stock from 5,000,000 shares to 1,000,000 shares.
Secretary of State of the State of Delaware [Member]
Stockholders' Equity (Textual)
Description of preferred stock, authorized		The Company filed with the Secretary of State of the State of Delaware a Certificate of Amendment to decrease the authorized number of preferred shares, consequently reducing the number of total authorized shares from 13,200,000 to 9,200,000.