Note 12—Stock-Based Compensation      

A summary of the activity and related information of the stock options issued under the 2018 Equity Incentive Plan and the 2018 Stock Compensation Plan is presented below:

A summary of the activity and related information of the restricted stock units issued under the 2018 Plan is presented below:

A summary of the activity and related information of the restricted stock awards issued under the 2018 Plan is presented below:

Stock-based compensation expense recorded in operating expenses was as follows (in thousands):

Stock-based compensation amounts of $0.1 million were capitalized to inventory and property and equipment during each of the three months ended March 31, 2021 and 2020, respectively.   

Unrecognized compensation expense for stock options issued as of March 31, 2021 was $0.9 million and is expected to be recognized over a weighted-average period of 1.5 years. Unrecognized compensation expense for the restricted stock units as of March 31, 2021 was $0.5 million and is expected to be recognized over a weighted-average period of 1.9 years. Unrecognized compensation expense for the restricted stock awards as of March 31, 2021 was $1.3 million and is expected to be recognized over a weighted-average period of 2.3 years.