Stockholders' Equity	9 Months Ended
Sep. 30, 2018
Equity [Abstract]
STOCKHOLDERS' EQUITY	5. STOCKHOLDERS’ EQUITY Common shares reserved As of September 30, 2018, the Company had reserved 113,643 shares of common stock for issuance upon the exercise of outstanding common stock options and vesting of restricted stock units (“RSUs”). Also, 303,443 shares of the Company’s common stock were reserved for future grants of stock options and RSUs (or other similar equity instruments) under the Rubicon Technology, Inc. 2016 Stock Incentive Plan (the “2016 Plan”) as of September 30, 2018. Preferred stock At the Company’s annual meeting of stockholders held on May 10, 2018, the Company’s stockholders approved an amendment to the Company’s Eighth Amended and Restated Certificate of Incorporation (as amended, the “Certificate of Incorporation”) to decrease the Company’s authorized number of shares of preferred stock from 5,000,000 shares to 1,000,000 shares. 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.

Stockholders' Equity

9 Months Ended

Sep. 30, 2018

5. STOCKHOLDERS’ EQUITY

Common shares reserved

As of September 30, 2018, the Company had reserved 113,643 shares of common stock for issuance upon the exercise of outstanding common stock options and vesting of restricted stock units (“RSUs”). Also, 303,443 shares of the Company’s common stock were reserved for future grants of stock options and RSUs (or other similar equity instruments) under the Rubicon Technology, Inc. 2016 Stock Incentive Plan (the “2016 Plan”) as of September 30, 2018.

Preferred stock

At the Company’s annual meeting of stockholders held on May 10, 2018, the Company’s stockholders approved an amendment to the Company’s Eighth Amended and Restated Certificate of Incorporation (as amended, the “Certificate of Incorporation”) to decrease the Company’s authorized number of shares of preferred stock from 5,000,000 shares to 1,000,000 shares. 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.