Net Loss Per Share (Details) - USD ($) |
3 Months Ended | 9 Months Ended | |||
---|---|---|---|---|---|
Sep. 30, 2017 |
Sep. 30, 2016 |
Sep. 30, 2017 |
Sep. 30, 2016 |
Dec. 21, 2016 |
|
Earnings Per Share [Abstract] | |||||
Weighted-average common shares outstanding (in shares) | 150,927,825 | 130,436,038 | 150,128,204 | 112,819,041 | |
Securities Financing Transaction [Line Items] | |||||
Fees and issuance costs | $ 638,000 | $ 1,340,000 | |||
Citigroup Global Markets Inc. | Equity Distribution Agreement | |||||
Securities Financing Transaction [Line Items] | |||||
Equity financing agreement, amount authorized (up to) | $ 200,000,000 | ||||
Gross proceeds | $ 0 | $ 16,066,000 | 10,767,000 | 69,113,000 | |
Fees and issuance costs | 0 | 386,000 | 311,000 | 1,728,000 | |
Net proceeds | $ 0 | $ 15,680,000 | $ 10,456,000 | $ 67,385,000 | |
Shares issued (in shares) | 0 | 3,824,144 | 3,802,500 | 21,325,587 |