Condensed consolidated statements of stockholders' equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Deficit [Member]
Balances at Dec. 31, 2018	$ 72,672		$ 302,759	$ (230,087)
Balances, shares at Dec. 31, 2018		23,537,368
Stock-based compensation (Note 5(d))	1,078		1,078
Net loss	(2,208)			(2,208)
Balances at Mar. 31, 2019	71,542		303,837	(232,295)
Balances, shares at Mar. 31, 2019		23,537,368
Balances at Dec. 31, 2019	141,687		441,216	(299,529)
Balances, shares at Dec. 31, 2019		37,996,849
Options exercised	$ 3,392		3,392
Options exercised, shares	376,311	376,311
Restricted stock units vested, shares		13,000
Stock-based compensation (Note 5(d))	$ 683		683
Net loss	(8,642)			(8,642)
Balances at Mar. 31, 2020	$ 137,120		$ 445,291	$ (308,171)
Balances, shares at Mar. 31, 2020		38,386,160