Leases - Future Minimum Lease Payments (Details) - USD ($)	Mar. 31, 2019	Dec. 31, 2018
Operating Leases
2019 (excluding the three months ended March 31, 2019)	$ 1,766,000
2020	2,397,000
2021	2,446,000
2022	2,483,000
2023	2,509,000
Thereafter	13,725,000
Total undiscounted lease payments	25,326,000
Less: Imputed interest	(6,213,000)
Total lease liabilities	19,113,000	$ 0
Finance Leases
2019 (excluding the three months ended March 31, 2019)	112,000
2020	120,000
2021	120,000
2022	120,000
2023	120,000
Thereafter	4,060,000
Total undiscounted lease payments	4,652,000
Less: Imputed interest	(539,000)
Total lease liabilities	$ 4,113,000	$ 4,100,000