Stockholders' Equity - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended		3 Months Ended		9 Months Ended
	Jul. 31, 2020	Apr. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Jan. 01, 2021	Jan. 01, 2020
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Reduction in exercise price of each warrant from public offering price for pre-funded warrants per share		$ 0.0001
Maximum ownership percentage for outstanding warrants to purchase shares of common stock to be exercised		4.99%
Period after notice received by company maximum ownership percentage to be effective description					The revised Maximum Ownership Percentage would be effective 61 days after the notice is received by the Company
Ownership percentage for outstanding warrants To purchase shares of common stock to be exercised to certain holders.		9.99%
2016 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of outstanding share of common stock					4.00%
Additional number of shares available for issuance							1,918,363	1,163,377
Common stock available for future issuance			1,369,881		1,369,881
2016 Equity Incentive Plan | Restricted Stock Units RSU
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock option to purchase an aggregate of common stock shares	228,200			228,200		228,200
Total stock-based compensation expense					$ 1.9	$ 1.9
2016 Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock option to purchase an aggregate of common stock shares			44,957	33,965	82,965	59,893
Aggregate cash proceeds from sale of shares			$ 0.2	$ 0.2	$ 0.4	$ 0.4
Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Maximum ownership percentage for outstanding warrants to purchase shares of common stock to be exercised		19.99%