Stock Based Compensation (Tables)

3 Months Ended

Mar. 31, 2021

Share-based Payment Arrangement [Abstract]

Summary of Options Granted, Exercised, Expired and Forfeited

A summary of stock options expired and forfeited under our plans and options outstanding as of, and changes made during, the three months ended March 31, 2021 and the year ended December 31, 2020 is presented below:

	Outstanding and Exercisable
	Number of Options	Weighted Average Exercise Price
Options outstanding and exercisable, December 31, 2019	215,345	$	12.27
Expired	(107,845)	4.92
Forfeited	—	—
Options outstanding and exercisable, December 31, 2020	107,500	19.64
Options outstanding and exercisable, March 31, 2021	107,500	$	19.64

Shares Outstanding and Exercisable, By Exercise Price Range

Additional information as of March 31, 2021 is as follows:

	Outstanding and Exercisable
Range of price	Number of Options	Weighted Average Remaining Contractual Life (In Years)	Weighted Average Exercise Price
$0.00 – $10.00	2,500	2.20	$	9.00
$10.01 – $20.00	97,500	1.81	19.32
$20.01 – $30.00	2,500	1.19	21.80
$30.01 – $40.00	5,000	0.96	30.20
	107,500	1.76	$	19.64

Schedule of Compensation Expense

Stock-based compensation expense relating to Restricted Series D Preferred Stock is allocated as follows (in thousands):

	Three Months Ended March 31,
	2021		2020
Research and development	$	17	$	47
Sales, general and administrative	$	16	$	111
	$	33	$	158