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Stock-based Compensation - Narrative (Details) - USD ($)	3 Months Ended			6 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 2,772,000		$ 2,697,000	$ 5,232,000	$ 5,117,000
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)				1,259,331	2,013,173
Weighted average grant date fair value (usd per share)				$ 3.44	$ 4.80
Unrecognized cost related to unvested RSUs expected to vest	17,030,000			$ 17,030,000
Estimated weighted-average amortization period				2 years 3 months 14 days
Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period				4 years
Granted (in shares)		1,290,203		1,290,203
Restricted shares fair value at grant date (usd per share)				$ 5.41
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	3,502,000			$ 3,502,000
Estimated weighted-average amortization period				3 years 8 months 15 days
Granted (in shares)				718,150
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	$ 137,000		$ 114,000	$ 287,000	$ 228,000
Inventory
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense				$ 52,000
Prepaid expenses and other assets
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense					$ 1,000