Stock-Based Awards (Details) - shares		12 Months Ended
	Jan. 01, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Sep. 30, 2015
Stock-based awards
Number of Shares, Granted		2,241,550	2,548,750	1,068,100
Options outstanding		6,419,455	5,167,164	3,792,450	2,871,498
Stock Option Valuation
Risk-free interest rate (as a percent)		3.55%	2.22%	0.92%
Expected term (in years)		6 years 2 months 12 days	6 years 2 months 12 days	6 years 2 months 12 days
Expected volatility (as a percent)		77.73%	77.95%	76.60%
Expected dividend yield (as a percent)		0.00%	0.00%	0.00%
2017 Inducement Plan
Stock-based awards
Options outstanding		370,600
2015 Equity Incentive Plan
Stock-based awards
Number of shares authorized						1,643,872
Number of shares available for grant		3,703,234
Percentage increase to shares available for grant from common outstanding as of preceding December 31 (as a percent)		4.00%
Additional shares available	2,835,795
Options outstanding		5,668,063
2015 Equity Incentive Plan | Restricted stock unit awards
Stock-based awards
Number of shares outstanding		1,521,940
2012 Equity Compensation Plan
Stock-based awards
Number of shares available for grant		0
Options outstanding		380,792