CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($)	Common Stock	Additional Paid-in Capital	Treasury Stock	Accumulated Other Comprehensive Income	Accumulated Deficit	Total
Balance at Dec. 31, 2018	$ 53,000	$ 249,727,000	$ 29,231	$ (2,000)	$ (181,453,000)	$ 68,325,000
Balance (in shares) at Dec. 31, 2018	52,548,244
Increase (Decrease) in Stockholders' Equity (Deficit)
Stock-based compensation expense		1,836,000				1,836,000
Exercise of stock options		65,000				65,000
Exercise of stock options (in shares)	55,812
Forfeiture of restricted stock (in shares)	(20,200)
Unrealized gain on investments				2,000		2,000
Net loss					(12,483,000)	(12,483,000)
Balance at Mar. 31, 2019	$ 53,000	251,628,000	29,231		(193,936,000)	57,745,000
Balance (in shares) at Mar. 31, 2019	52,583,856
Balance at Dec. 31, 2019	$ 87,000	295,056,000	29,231		(235,574,000)	59,569,000
Balance (in shares) at Dec. 31, 2019	86,500,353
Increase (Decrease) in Stockholders' Equity (Deficit)
Stock-based compensation expense		1,876,000				1,876,000
Exercise of stock options		312,000				312,000
Exercise of stock options (in shares)	239,913
Issuance of restricted stock (in shares)	21,000
Unrealized gain on investments				28,000		28,000
Deemed dividend on beneficial conversion feature - Series A convertible preferred stock		8,880,000			(8,880,000)
Net loss					(18,672,000)	(18,672,000)
Balance at Mar. 31, 2020	$ 87,000	$ 306,124,000	$ 29,231	$ 28,000	$ (263,126,000)	$ 43,113,000
Balance (in shares) at Mar. 31, 2020	86,761,266