|
Stockholders' equity (Details) (USD $)
In Thousands, except Share data, unless otherwise specified |
0 Months Ended | 1 Months Ended | 12 Months Ended | 5 Months Ended | 12 Months Ended | 5 Months Ended | 12 Months Ended | 5 Months Ended | 12 Months Ended | 5 Months Ended | 12 Months Ended | |||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
Jun. 28, 2011
|
Jan. 11, 2011
|
Jul. 31, 2011
|
Dec. 31, 2011
|
Dec. 31, 2002
|
Dec. 31, 2012
|
May 03, 2011
|
Dec. 31, 2010
|
Dec. 31, 2009
|
Jun. 28, 2011
Common stock warrants
|
Dec. 31, 2012
2001 Plan
|
Dec. 31, 2011
2001 Plan
|
Dec. 31, 2012
2011 Plan
|
Dec. 31, 2011
2011 Plan
|
May 03, 2011
Series A convertible preferred stock
|
Dec. 31, 2010
Series A convertible preferred stock
|
Dec. 31, 2009
Series A convertible preferred stock
|
Jul. 31, 2001
Series A convertible preferred stock
|
May 03, 2011
Series A-2 convertible preferred stock
|
Dec. 31, 2010
Series A-2 convertible preferred stock
|
Dec. 31, 2009
Series A-2 convertible preferred stock
|
Feb. 28, 2002
Series A-2 convertible preferred stock
|
May 03, 2011
Series B convertible preferred stock
|
Dec. 31, 2010
Series B convertible preferred stock
|
Dec. 31, 2009
Series B convertible preferred stock
|
Dec. 31, 2003
Series B convertible preferred stock
|
May 03, 2011
Series C convertible preferred stock
|
Dec. 31, 2010
Series C convertible preferred stock
|
Dec. 31, 2009
Series C convertible preferred stock
|
Sep. 30, 2006
Series C convertible preferred stock
|
|
| Stockholders' equity (deficit) | ||||||||||||||||||||||||||||||
| Convertible preferred stock, shares issued | 5,052,566 | 1,104,969 | 3,433,326 | 10,983,188 | ||||||||||||||||||||||||||
| Preferred stock issued (in shares) | 0 | 0 | ||||||||||||||||||||||||||||
| Preferred stock outstanding (in shares) | 0 | 0 | ||||||||||||||||||||||||||||
| Conversion price (in dollars per share) | $ 3.00 | $ 4.026072935 | $ 3.00 | $ 4.95835 | ||||||||||||||||||||||||||
| Convertible preferred stock conversion ratio | 1 | 1.07 | 1 | 1.2 | ||||||||||||||||||||||||||
| Multiplier for number of shares converted (in dollars per share) | $ 4.30 | $ 5.95 | ||||||||||||||||||||||||||||
| Cumulative dividends per annum on preferred stock (in dollars per share) | $ 0.15 | $ 0.15 | $ 0.15 | $ 0.215 | $ 0.215 | $ 0.215 | $ 0.15 | $ 0.15 | $ 0.15 | $ 0.2975 | $ 0.2975 | $ 0.2975 | ||||||||||||||||||
| Common stock authorized (in shares) | 100,000,000 | 100,000,000 | ||||||||||||||||||||||||||||
| Common Stock reserved | ||||||||||||||||||||||||||||||
| Outstanding stock options (in shares) | 6,601,000 | 5,045,000 | 5,288,000 | 5,281,000 | 2,345,000 | 4,340,000 | 2,700,000 | 2,261,000 | ||||||||||||||||||||||
| Number of shares available for grant (in shares) | 2,811,000 | 1,739,000 | ||||||||||||||||||||||||||||
| Total (in shares) | 8,340,000 | 7,856,000 | ||||||||||||||||||||||||||||
| Note receivable from stockholder | ||||||||||||||||||||||||||||||
| Restricted common stock (in shares) | 290,000 | |||||||||||||||||||||||||||||
| Restricted common stock at deemed fair value (in dollars per share) | $ 0.30 | |||||||||||||||||||||||||||||
| Cash proceeds from restricted common stock granted | $ 9 | |||||||||||||||||||||||||||||
| Note receivable from shareholder with an interest rate equal to the applicable federal rate | 78 | |||||||||||||||||||||||||||||
| Forgiveness of note receivable from stockholder and principal and interest outstanding | 103 | 103 | ||||||||||||||||||||||||||||
| Treasury stock | ||||||||||||||||||||||||||||||
| Retirement of outstanding shares of treasury stock | 1,256,608 | |||||||||||||||||||||||||||||
| Retirement of treasury stock | $ 4,575 | |||||||||||||||||||||||||||||
| Common stock warrants | ||||||||||||||||||||||||||||||
| Common stock warrants outstanding (in shares) | 25,196 | 26,322 | ||||||||||||||||||||||||||||
| Warrants exercised into shares (in shares) | 21,525 | |||||||||||||||||||||||||||||