|
Capital Stock, Other Offerings and Agreements (Details) (USD $)
|
12 Months Ended | 1 Months Ended | 3 Months Ended | 12 Months Ended | 16 Months Ended | 11 Months Ended | 12 Months Ended | 11 Months Ended | 12 Months Ended | 1 Months Ended | ||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
Dec. 31, 2012
|
Dec. 31, 2011
|
Dec. 31, 2010
|
Jun. 30, 2009
Registered Direct Offerings [Member]
|
Sep. 30, 2009
2009 ATM Agreement [Member]
|
Dec. 31, 2010
2009 ATM Agreement [Member]
|
Oct. 31, 2010
2009 ATM Agreement [Member]
|
May 31, 2011
2010 ATM Agreement [Member]
|
Dec. 31, 2011
2010 ATM Agreement [Member]
|
Dec. 31, 2011
2011 ATM Agreement [Member]
|
Dec. 31, 2012
2011 ATM Agreement [Member]
|
Oct. 31, 2012
Underwritten Offering [Member]
|
Mar. 31, 2012
Underwritten Offering [Member]
|
Feb. 28, 2010
Underwritten Offering [Member]
|
Oct. 29, 2012
Underwritten Offering [Member]
|
Mar. 09, 2012
Underwritten Offering [Member]
|
|
| Registered Direct Offerings and Underwritten Offering [Abstract] | ||||||||||||||||
| Capital units issued (in shares) | 695,652 | 2,800,000 | 13,333,333 | 29,669,154 | ||||||||||||
| Common stock per capital unit (in shares) | 1 | 1 | 0.5 | |||||||||||||
| Common stock per capital unit called by stock warrant (in shares) | 0.50 | 0.45 | ||||||||||||||
| Gross proceeds from issuance of capital units | $ 12,000,000 | $ 40,000,000 | $ 39,200,000 | $ 21,000,000 | ||||||||||||
| Offering expense | 800,000 | 400,000 | 1,000,000 | 100,000 | 3,000,000 | 3,000,000 | ||||||||||
| Purchase price of capital units (in dollars per share) | $ 17.25 | $ 3.00 | $ 1.32 | |||||||||||||
| Number of shares called by warrants (in shares) | 347,826 | 14,834,577 | ||||||||||||||
| Exercise price of warrants (in dollars per share) | $ 19.50 | $ 1.76 | ||||||||||||||
| Over allotment option (in shares) | 1,999,999 | |||||||||||||||
| Period to purchase additional stock | 30 days | |||||||||||||||
| Term of warrants | 5 years | |||||||||||||||
| Warrant outstanding (in shares) | 14,265,970 | |||||||||||||||
| ATM Agreement [Abstract] | ||||||||||||||||
| Maximum number of shares of common stock reserved for sale under agreement (in shares) | 1,700,000 | |||||||||||||||
| Common stock sold (in shares) | 1,400,000 | 1,700,000 | 7,560,862 | 821,386 | 7,572,327 | 0 | ||||||||||
| Sales commission paid per transaction (in hundredths) | 3.00% | 3.00% | ||||||||||||||
| Minimum sales price (in dollars per share) | $ 0.02 | |||||||||||||||
| Proceeds from issuance of common stock | $ 77,491,000 | $ 15,143,000 | $ 70,771,000 | $ 9,300,000 | $ 12,200,000 | $ 34,000,000 | $ 4,400,000 | $ 14,600,000 | $ 500,000 | |||||||