The business (Details 2) (USD $) In Thousands, except Share data, unless otherwise specified	0 Months Ended
	May 03, 2011
Initial public offering
Common stock offered (in shares)	3,846,800
Public offering of common stock held by selling stockholders (in shares)	1,923,200
Proceeds from initial public offering after deducting underwriting discount, commission and offering expenses	$ 45,701
Underwriting discounts and commissions on public offering	3,635
Offering expenses on public offering	2,596
Issuance of common stock upon conversion of preferred stock (in shares)	22,845,764
Issuance of common stock upon exercise and conversion of preferred stock warrants (in shares)	20,172
Reverse stock split
Ratio for reverse stock split of outstanding common stock	5
Fractional shares settled in cash for common and preferred stockholders	$ 1
Number of fractional shares settled in cash for common and preferred stockholders	0