Consolidated Statement of Stockholders' Equity (Deficit) - USD ($) $ in Thousands	Common Stock [Member] Class A common stock	Common Stock [Member] Common Class B [Member]	Additional Paid-in Capital [Member]	Accumulated Deficit	Noncontrolling Interest [Member]	Total
Stockholders' Equity, Beginning Balance at Dec. 31, 2018	$ 329	$ 155	$ 251,742	$ (17,335)	$ 3,496	$ 238,387
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Share based compensation			856			856
Vesting of restricted units		1	(39)			(38)
Net income (loss)				4,721	298	5,019
Stockholders' Equity, Ending Balance at Mar. 31, 2019	329	156	252,559	(12,614)	3,794	244,224
Stockholders' Equity, Beginning Balance at Dec. 31, 2019	333	157	250,700	(20,982)	628	230,836
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Share based compensation			836			836
Issuance of common stock under ESPP, value	1		419			420
Vesting of restricted units	1	1	(93)			(91)
Net income (loss)				(9,216)	(16)	(9,232)
Stockholders' Equity, Ending Balance at Mar. 31, 2020	$ 335	$ 158	$ 251,862	$ (30,198)	$ 612	$ 222,769