Statement of Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Statement of Comprehensive Income
Net income (loss)	$ (1,812)	$ 1,520	$ 2,245	$ 4,041
Other comprehensive income:
Unrealized gains on marketable securities	5		5
Total other comprehensive income	5		5
Total comprehensive income (loss)	$ (1,807)	$ 1,520	$ 2,250	$ 4,041