Note 2 - Stock-Based Compensation and Stock Option Activity (Detail) - Stock Option Activity Under Equity Incentive Plan (USD $)	12 Months Ended
	Dec. 31, 2012
Total options outstanding	1,097,236
Total options outstanding (in Dollars per share)	$ 4.58
Options Outstanding [Member]
Total options outstanding	1,579,410
Total options outstanding (in Dollars per share)	$ 6.81
Options granted	241,000
Options granted (in Dollars per share)	$ 3.26
Options exercised	(25,375)
Options exercised (in Dollars per share)	$ 1.93
Options forfeited and cancelled	(697,799)
Options forfeited and cancelled (in Dollars per share)	$ 9.27
Options Exercisable [Member]
Options exercisable at December 31, 2012	660,828
Options exercisable at December 31, 2012 (in Dollars per share)	$ 5.34
Options exercisable at December 31, 2012	4 years
Options exercisable at December 31, 2012 (in Dollars)	$ 179,529	[1]
Options vested and expected to vest at December 31, 2012	4 years
Options Vested And Expected To Vest [Member]
Options exercisable at December 31, 2012	5 years 277 days
Options vested and expected to vest at December 31, 2012	1,064,995
Options vested and expected to vest at December 31, 2012 (in Dollars per share)	$ 4.62
Options vested and expected to vest at December 31, 2012	5 years 277 days
Options vested and expected to vest at December 31, 2012 (in Dollars)	$ 382,012	[1]

[1] Aggregate intrinsic value is calculated as the difference between the exercise price of the underlying awards and the quoted price of Onvia's common stock of $3.68 at December 31, 2012 for options that were in-the-money at December 31, 2012. The number of in-the-money options outstanding and exercisable at December 31, 2012 was 526,702 and 195,715, respectively.