XML 47 R29.htm IDEA: XBRL DOCUMENT
v2.4.0.6

Summary of Significant Accounting Policies (Tables) | 12 Months Ended
--- | ---
Dec. 31, 2012
Accounting Policies [Abstract] |
Summary of common shares that were excluded from the diluted net loss per share calculation because of their anti-dilutive effect | The following table summarizes potential common shares that were excluded from diluted net loss per share calculation because of their anti-dilutive effect:
| Year Ended December 31,
Common Stock Equivalents | 2012 |  | 2011 |  | 2010
Options to purchase common stock | 16,257,444 |  |  | 14,302,803 |  |  | 12,649,968 |
Warrants to purchase common stock | 21,593,844 |  |  | 21,743,844 |  |  | 7,771,133 |
Convertible preferred stock | 38,233 |  |  | 38,233 |  |  | 38,233 |
Total | 37,889,521 |  |  | 36,084,880 |  |  | 20,459,334 |
Summary of assumptions used to estimate the fair value of stock options | Weighted average assumptions used in the Black-Scholes model for employees and directors are presented below:
| Year Ended December 31,
| 2012 |  | 2011 |  | 2010
Risk-free interest rate | 0.36% |  | 1.23% |  | 1.09% – 2.65%
Expected volatility | 131% |  | 134% |  | 134%
Expected life in years | 4 |  | 4 |  | 4
Dividend yield | — |  | — |  | —
Forfeiture rate | 8% |  | 11% |  | 11%
Assumptions used in the Black-Scholes model for non-employees are presented below:
| Year Ended December 31,
| 2012 |  | 2011 |  | 2010
Risk-free interest rate | 0.67% – 0.83% |  | 0.91% – 3.47% |  | 1.89% – 3.84%
Expected volatility | 103%-117% |  | 96%-119% |  | 71%-120%
Expected life in years | 7-10 |  | 6-10 |  | 7-10
Dividend yield | — |  | — |  | —

X
- Details
Name: | us-gaap_AccountingPoliciesAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) in the future that were not included in the computation of diluted EPS because to do so would increase EPS amounts or decrease loss per share amounts for the period presented, by antidilutive securities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 260 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=6371337&loc=d3e3550-109257 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 128 -Paragraph 40 -Subparagraph c -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. + Details
Name: | us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of the significant assumptions used during the year to estimate the fair value of stock options, including, but not limited to: (a) expected term of share options and similar instruments, (b) expected volatility of the entity's shares, (c) expected dividends, (d) risk-free rate(s), and (e) discount for post-vesting restrictions. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (f)(2) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
Name: | us-gaap_ScheduleOfShareBasedPaymentAwardStockOptionsValuationAssumptionsTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration