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Stock-based Compensation - Narrative (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 2,626,000	$ 2,435,000	$ 7,857,000	$ 7,552,000
Plan options contractual life (up to)			10 years
Award vesting period			4 years
Service Based Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period			4 years	4 years
Stock options to purchase shares (in shares)			1,303,210	2,070,173
Weighted average grant date fair value (usd per share)			$ 3.44	$ 4.78
Unrecognized cost related to unvested RSUs expected to vest	14,082,000		$ 14,082,000
Estimated weighted-average amortization period			2 years 1 month 17 days
Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period			4 years
Granted (in shares)			1,542,172
Restricted shares fair value at grant date (usd per share)			$ 5.27
Restricted Stock Units, Service-Based
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized cost related to unvested RSUs expected to vest	4,260,000		$ 4,260,000
Estimated weighted-average amortization period			3 years 5 months 12 days
Granted (in shares)			970,119
Restricted Stock Units, Performance-Based
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense			$ 0
Unrecognized cost related to unvested RSUs expected to vest	3,095,000		$ 3,095,000
Granted (in shares)			572,053
NASDAQ Inducement Grant Exception \| Service Based Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options to purchase shares (in shares)			90,000
NASDAQ Inducement Grant Exception \| Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)			60,000
2017 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 102,000	$ 91,000	$ 389,000	$ 319,000
Inventory
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense			68,000
Prepaid expenses and other assets
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense			$ 1,000