Note 13 - Equity-based Compensation - Stock Options Outstanding (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Outstanding awards (in shares)	3,374,000	2,960,000	1,489,000
Outstanding, weighted-average exercise price (in dollars per share)	$ 4.13	$ 5.16	$ 8.38
Outstanding, weighted-average remaining contractual life (Year)	6 years 219 days	8 years 73 days	8 years 219 days	8 years 255 days
Outstanding, aggregate intrinsic value	$ 43	$ 8	$ 2,586	$ 702
Options granted (in shares)	145,000	1,118,000	1,616,000
Options granted, weighted-average exercise price (in dollars per share)	$ 0.37	$ 2.03	$ 3.03
Options exercised (in shares)	(83,000)	(4,000)	(68,000)
Options exercised, weighted-average exercise price (in dollars per share)	$ 2.30	$ 2.35	$ 2.72
Options forfeited/cancelled (in shares)	(1,247,000)	(701,000)	(87,000)
Options forfeited/cancelled, weighted-average exercise price (in dollars per share)	$ 4.01	$ 5.12	$ 22.08
Outstanding awards (in shares)	2,183,000	3,374,000	2,960,000	1,489,000
Outstanding, weighted-average exercise price (in dollars per share)	$ 4.03	$ 4.13	$ 5.16	$ 8.38
Vested and expected to vest (in shares)	2,165,000
Vested and expected to vest, weighted-average exercise price (in dollars per share)	$ 4.05
Vested and expected to vest, weighted-average remaining contractual life (Year)	6 years 182 days
Vested and expected to vest, aggregate intrinsic value	$ 43
Vested (in shares)	1,818,000
Vested, weighted-average exercise price (in dollars per share)	$ 4.44
Vested, weighted-average remaining contractual life (Year)	6 years 73 days
Exercisable (in shares)	1,818,000
Exercisable, weighted-average exercise price (in dollars per share)	$ 4.44
Exercisable, weighted-average remaining contractual life (Year)	6 years 73 days
Restricted Stock Units (RSUs) [Member]
Restricted stock units granted (in shares)	204,000	12,000	49,000
Restricted stock units granted, weighted-average exercise price (in dollars per share)
Options exercised (in shares)		(4,000)
Restricted stock units vested (in shares)	(209,000)		(39,000)
Restricted stock units vested, weighted-average exercise price (in dollars per share)
Restricted stock units cancelled (in shares)	(1,000)	(11,000)