Note 6 - Redeemable Convertible Preferred Stock (Details) (USD $)	9 Months Ended		3 Months Ended	9 Months Ended										0 Months Ended					0 Months Ended	2 Months Ended
	Sep. 30, 2014	May 13, 2014	Sep. 30, 2014 Other Expense [Member] Series D Preferred Stock [Member] Rights [Member]	Sep. 30, 2014 Other Expense [Member] Series D Preferred Stock [Member] Rights [Member]	Sep. 30, 2014 Redeemable Preferred Stock [Member]	Sep. 30, 2014 Series A Preferred Stock [Member]	Dec. 31, 2013 Series A Preferred Stock [Member]	Sep. 30, 2014 Series A-1 Preferred Stock [Member]	Dec. 31, 2013 Series A-1 Preferred Stock [Member]	Sep. 30, 2014 Series B Preferred Stock [Member]	Dec. 31, 2013 Series B Preferred Stock [Member]	Sep. 30, 2014 Series C Preferred Stock [Member]	Dec. 31, 2013 Series C Preferred Stock [Member]	May 13, 2014 Series D Preferred Stock [Member] Second and Third Tranches [Member]	May 13, 2014 Series D Preferred Stock [Member]	Sep. 30, 2014 Series D Preferred Stock [Member]	May 13, 2014 Series D Preferred Stock [Member]	Dec. 31, 2013 Series D Preferred Stock [Member]	Oct. 21, 2014 IPO [Member] Subsequent Event [Member]	Nov. 21, 2014 IPO [Member] Subsequent Event [Member]	Oct. 21, 2014 IPO [Member] Subsequent Event [Member]
Note 6 - Redeemable Convertible Preferred Stock (Details) [Line Items]
Temporary Equity, Shares Authorized					364,568,592	22,638,465	22,638,465	10,909,091	10,909,091	20,754,461	20,754,461	17,550,758	17,550,758			86,789,527		0
Temporary Equity, Par or Stated Value Per Share (in Dollars per share)						$ 0.001	$ 0.001	$ 0.001	$ 0.001	$ 0.001	$ 0.001	$ 0.001	$ 0.001			$ 0.001		$ 0.001
Temporary Equity, Shares Issued						22,638,465	22,638,465	10,909,091	10,909,091	20,754,461	20,754,461	13,202,932	13,202,932			52,813,827	42,469,626	0
Share Price (in Dollars per share)																	$ 0.588656				$ 10
Proceeds from Issuance or Sale of Equity (in Dollars)														$ 20,000,000	$ 25,000,000
Convertible Notes Payable, Noncurrent (in Dollars)																	4,600,000
Interest on Convertible Debt, Net of Tax (in Dollars)															200,000
Debt Conversion, Converted Instrument, Shares Issued															10,344,201
Debt Instrument, Convertible, Conversion Price (in Dollars per share)																	$ 0.4414
Temporary Equity, Additional Shares Issuable														33,975,700
Class of Warrant or Right, Number of Securities Called by Warrants or Rights		0.588656
(in Dollars)	11,903,000																6,600,000
Fair Value, Option, Changes in Fair Value, Gain (Loss) (in Dollars)			5,300,000	5,300,000
Payments of Stock Issuance Costs (in Dollars)	452,000														500,000					7,700,000
Amortization of Financing Costs and Discounts (in Dollars)															400,000
Allocated To Trance Right Liability (in Dollars)																	$ 100,000
Conversion of Stock, Shares Issued																			8,651,805