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Common Stock - Additional Information (Detail) (USD $)
In Millions, except Share data, unless otherwise specified |
9 Months Ended | 12 Months Ended | 9 Months Ended | 3 Months Ended | 9 Months Ended | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
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Sep. 30, 2013
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Sep. 30, 2012
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Dec. 31, 2012
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Sep. 30, 2013
Stock Option [Member]
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Sep. 30, 2013
Stock Option [Member]
Minimum [Member]
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Sep. 30, 2013
Stock Option [Member]
Maximum [Member]
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Sep. 30, 2013
Stock Option [Member]
Employees And Consultants [Member]
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Sep. 30, 2013
Stock Option [Member]
Board Of Directors [Member]
Minimum [Member]
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Sep. 30, 2013
Stock Option [Member]
Board Of Directors [Member]
Maximum [Member]
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Sep. 30, 2013
Restricted stock units [Member]
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Sep. 30, 2012
Restricted stock units [Member]
|
Sep. 30, 2013
Restricted stock units [Member]
|
Sep. 30, 2012
Restricted stock units [Member]
|
Jun. 18, 2013
MLV [Member]
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| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||||||||||||
| Common stock, shares authorized | 50,000,000 | 25,000,000 | ||||||||||||
| Common stock, par value | $ 0.001 | $ 0.001 | ||||||||||||
| Preferred stock, shares authorized | 5,000,000 | |||||||||||||
| Preferred stock, par value | $ 0.001 | |||||||||||||
| Common stock sales agreement aggregate offering amount | $ 25 | |||||||||||||
| Common stock sales agreement commission in percentage | 3.00% | |||||||||||||
| Number of shares issued for stock option exercises | 3,475 | 116,834 | ||||||||||||
| Number of shares issued for Restricted stock unit settlements | 45,869 | |||||||||||||
| Common shares reserved for issuance under various plans | 2,381,607 | |||||||||||||
| Common shares reserved for options currently outstanding | 985,616 | 352,313 | 352,313 | |||||||||||
| Common shares available for future equity grants | 1,043,678 | |||||||||||||
| Award vesting period | 4 years | 1 year | 3 years | 4 years | ||||||||||
| Award expiration period | 7 years | 10 years | ||||||||||||
| Unrecognized compensation expense related to stock options granted | 3.0 | 2.7 | ||||||||||||
| Weighted-average period, restricted stock awards | 2 years 4 months 24 days | 2 years 9 months 18 days | ||||||||||||
| Effect on diluted per share on options, restricted stock units and warrants | 2,900,000 | 2,600,000 | ||||||||||||
| Stock-based compensation expense | 0.5 | 0.2 | 1.2 | 0.4 | ||||||||||
| Total unrecognized compensation expense related to the Company's restricted stock awards | $ 2.5 | $ 2.5 | ||||||||||||
| Warrants outstanding | 1,587,301 | |||||||||||||
| Exercise price of warrants | $ 20 | |||||||||||||
| Warrants expiration date | 2015-10 | |||||||||||||
| Warrants exercised | 0 | 0 | ||||||||||||