Stock-based Compensation - Expense for Stock-Based Awards (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018
Compensation expense recognized
Stock-based compensation expense	$ 2,311	$ 3,098
Total unrecognized compensation costs related to unvested awards	$ 2,000
Weighted-average period of recognition for unrecognized compensation costs related to unvested awards	2 years 2 months 12 days
Selling and marketing
Compensation expense recognized
Stock-based compensation expense	$ 151	269
General and Administrative [Member]
Compensation expense recognized
Stock-based compensation expense	2,115	2,655
Research and development
Compensation expense recognized
Stock-based compensation expense	$ 45	$ 174

Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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