Subsequent Event	12 Months Ended
Dec. 31, 2012
Subsequent Event	17. Subsequent Event On March 18, 2013, the Company entered into at-the-market issuance sales agreements (the “ATM Agreements”) with two sales agents, under which the Company may issue and sell shares of its common stock having an aggregate offering price of up to $50.0 million under each ATM Agreement (provided that in no event may the Company issue and sell more than $50.0 million of shares of its common stock under both ATM Agreements in the aggregate) from time to time through either of the sales agents. Neither the Company nor either of the sales agents has any obligation to sell shares of the Company’s common stock under the ATM Agreements. Any sales of common stock made under the ATM Agreements will be made in “at the market” offerings as defined in Rule 415 of the Securities Act of 1933, as amended.

Subsequent Event

12 Months Ended

Dec. 31, 2012

17. Subsequent Event

On March 18, 2013, the Company entered into at-the-market issuance sales agreements (the “ATM Agreements”) with two sales agents, under which the Company may issue and sell shares of its common stock having an aggregate offering price of up to $50.0 million under each ATM Agreement (provided that in no event may the Company issue and sell more than $50.0 million of shares of its common stock under both ATM Agreements in the aggregate) from time to time through either of the sales agents. Neither the Company nor either of the sales agents has any obligation to sell shares of the Company’s common stock under the ATM Agreements. Any sales of common stock made under the ATM Agreements will be made in “at the market” offerings as defined in Rule 415 of the Securities Act of 1933, as amended.