Note 14 - Equity - Changes in Stockholders' Equity (Details) - USD ($)	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Balances	$ 97,783,756	$ 102,914,687
Net (loss)/income	$ (8,897,529)	1,629,777
Repurchase of common stock (in shares)	(225,094)
Repurchase of common stock	$ (993,375)
Payment of common stock tendered for employee stock-based compensation tax obligations	(9,746)	(56,590)
Issuance of common stock upon vesting of RSUs
Stock-based compensation	259,016	408,894
Issuance of common stock upon exercise of stock options
Issuance of common stock upon exercise of stock-settled appreciation rights
Issuance of common stock upon exercise of warrants		1,172,801
Balances	$ 88,142,122	$ 106,069,569
Common Stock [Member]
Balances (in shares)	81,269,868	80,763,350
Balances	$ 8,127	$ 8,076
Net (loss)/income
Repurchase of common stock (in shares)	(225,094)
Repurchase of common stock	$ (22)
Payment of common stock tendered for employee stock-based compensation tax obligations (in shares)	(1,892)	(8,148)
Payment of common stock tendered for employee stock-based compensation tax obligations		$ (1)
Issuance of common stock upon vesting of RSUs (in shares)	4,542
Issuance of common stock upon vesting of RSUs
Stock-based compensation
Issuance of common stock upon exercise of stock options (in shares)		9,769
Issuance of common stock upon exercise of stock options		$ 1
Issuance of common stock upon exercise of stock-settled appreciation rights (in shares)		16,771
Issuance of common stock upon exercise of stock-settled appreciation rights		$ 2
Issuance of common stock upon exercise of warrants (in shares)		159,782
Issuance of common stock upon exercise of warrants		$ 16
Balances (in shares)	81,047,424	80,941,524
Balances	$ 8,105	$ 8,094
Additional Paid-in Capital [Member]
Balances	220,808,037	218,697,872
Net (loss)/income
Repurchase of common stock
Payment of common stock tendered for employee stock-based compensation tax obligations	(9,746)	(56,589)
Issuance of common stock upon vesting of RSUs
Stock-based compensation	259,016	408,894
Issuance of common stock upon exercise of stock options		(1)
Issuance of common stock upon exercise of stock-settled appreciation rights		(2)
Issuance of common stock upon exercise of warrants		1,172,785
Balances	221,057,307	220,222,959
Retained Earnings [Member]
Balances	(123,032,408)	(115,791,261)
Net (loss)/income	(8,897,529)	1,629,777
Repurchase of common stock	(993,353)
Payment of common stock tendered for employee stock-based compensation tax obligations
Issuance of common stock upon vesting of RSUs
Stock-based compensation
Issuance of common stock upon exercise of stock options
Issuance of common stock upon exercise of stock-settled appreciation rights
Issuance of common stock upon exercise of warrants
Balances	(132,923,290)	(114,161,484)
AOCI Attributable to Parent [Member]
Balances
Net (loss)/income
Repurchase of common stock
Payment of common stock tendered for employee stock-based compensation tax obligations
Issuance of common stock upon vesting of RSUs
Stock-based compensation
Issuance of common stock upon exercise of stock options
Issuance of common stock upon exercise of stock-settled appreciation rights
Issuance of common stock upon exercise of warrants
Balances