Stock Option Plans (Tables)

3 Months Ended

Mar. 31, 2020

Stock Option Plans

Summary of stock option activity

		Options Outstanding
			Weighted‑
	Shares		Average
	Available	Number of	Exercise
	for Grant	Options	Price
Balance at December 31, 2019	1,704,183	5,643,410	$	8.05
Additional shares authorized	1,118,000	—		—
Options granted	(100,000)	100,000		2.14
Options forfeited	23,590	(23,590)		7.24
Balance at March 31, 2020	2,745,773	5,719,820	$	7.95