Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Accrued expenses:
Selling, general and administrative expenses	$ 5,615	$ 5,544
Research and development expenses	4,001	3,379
Payroll expenses	3,884	7,810
Product revenue allowances	12,016	12,858
Other	1,960	1,788
Total accrued expenses	27,476	31,379
Other current liabilities:
Lease liability	1,346	1,135
Total other current liabilities	1,346	1,135
Total accrued expenses and other current liabilities	$ 28,822	$ 32,514