Related Party Transactions - Narrative (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Related Party Transactions [Abstract]
Sublease, term of contract (years)	1 year
Future sublease payments receivable from related party		$ 0.4
Related Party Transaction, Description of Transaction	IRRAS AB ("IRRAS") is a commercial stage medical technology company of which a former director of the Company is also the President, Chief Executive Officer and director. In January 2018, the Company and IRRAS entered into a Sublease, pursuant to which the Company subleased to IRRAS excess capacity in its corporate headquarters. The sublease had a term of two years. On October 30, 2018, the Company and IRRAS entered into an amended and restated sublease, commencing January 1, 2019, pursuant to which the Company agreed to sublease to IRRAS the remainder of its San Diego, California location (the "IRRAS Restated Sublease"), which satisfied a closing condition related to the Merger. The IRRAS Restated Sublease has a term of one year and provides for aggregate payments due to the Company of approximately $0.4 million, which approximates fair value.