Subsequent Events	12 Months Ended
Dec. 31, 2018
Subsequent Events [Abstract]
Subsequent Events	16. Subsequent Events In February 2019, the Company issued and sold 4,625,000 shares of common stock at a public offering price of $8.00 per share and pre-funded warrants to purchase 4,000,000 shares of common stock at a public offering price of $7.9999 per warrant in an underwritten public offering pursuant to a shelf registration statement on Form S-3. This includes the full exercise by the underwriters of their option to purchase up to 1,125,000 additional shares of common stock. The net proceeds to the Company from this public offering were approximately $64.5 million, after deducting underwriting discounts and commissions of $4.1 million and estimated offering costs of $0.4 million.

The entire disclosure for significant events or transactions that occurred after the balance sheet date through the date the financial statements were issued or the date the financial statements were available to be issued. Examples include: the sale of a capital stock issue, purchase of a business, settlement of litigation, catastrophic loss, significant foreign exchange rate changes, loans to insiders or affiliates, and transactions not in the ordinary course of business.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 855
-URI http://asc.fasb.org/topic&trid=2122774

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