Share-Based Compensation - Narrative (Details) - USD ($) $ in Thousands	1 Months Ended					3 Months Ended		9 Months Ended		117 Months Ended
	May 31, 2022	Dec. 31, 2021	Sep. 30, 2021	Feb. 28, 2021	Mar. 31, 2020	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Oct. 31, 2019	Apr. 30, 2016
Stock options
Stock Option and Compensation Plans
Unrecognized share-based compensation costs for option awards, net of estimated forfeitures						$ 37,400		$ 37,400		$ 37,400
Expected weighted average period to recognize share-based compensation costs (in years)								2 years 10 months 24 days
Restricted stock units
Stock Option and Compensation Plans
Expected weighted average period to recognize share-based compensation costs (in years)								2 years 6 months
Unrecognized compensation costs, net of estimated forfeitures						$ 16,800		$ 16,800		$ 16,800
Employee stock purchase plan
Stock Option and Compensation Plans
Number of initial shares reserved for issuance under the Plan (in shares)												1,000,000
Number of shares available for future purchase (in shares)						712,394		712,394		712,394
Common stock issued (in shares)						25,921	27,529	41,016	51,951
Proceeds from stock plans						$ 331	$ 146	$ 515	$ 266
2013 Plan
Stock Option and Compensation Plans
Increase in number of shares available under the Plan (in shares)								2,542,000		15,624,000
Number of shares of common stock available for issuance under the Plan (in shares)						3,204,000		3,204,000		3,204,000
2019 Inducement Plan | Stock options
Stock Option and Compensation Plans
Increase in number of shares available under the Plan (in shares)	1,000,000	1,000,000	1,000,000	600,000	1,000,000
Number of shares of common stock available for issuance under the Plan (in shares)						1,245,000		1,245,000		1,245,000
Number of initial shares reserved for issuance under the Plan (in shares)											1,000,000