Summary of Significant Accounting Policies - Loss Per Share (Details) - shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Net Earnings per Share
Securities excluded from diluted loss per share calculation	12,968,474	12,624,103
Options to purchase common stock
Net Earnings per Share
Securities excluded from diluted loss per share calculation	8,598,149	8,244,605
Unvested restricted stock awards
Net Earnings per Share
Securities excluded from diluted loss per share calculation	146,800	146,800
Unvested restricted stock units
Net Earnings per Share
Securities excluded from diluted loss per share calculation	1,452,744	1,461,917
Warrants to purchase common stock
Net Earnings per Share
Securities excluded from diluted loss per share calculation	2,770,781	2,770,781