Commitments and Contingencies - Additional Information (Detail) $ / shares in Units, € in Millions						3 Months Ended		12 Months Ended
	Dec. 19, 2018 USD ($) $ / shares shares	Apr. 05, 2018 USD ($) $ / shares shares	Nov. 29, 2017 USD ($)	Oct. 23, 2017 shares	May 05, 2017 USD ($)	Dec. 31, 2018 USD ($)	Jun. 30, 2018 USD ($) Vehicle	Dec. 31, 2018 USD ($)	Dec. 31, 2018 EUR (€)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2018 EUR (€)	Sep. 07, 2018 $ / shares	Sep. 06, 2018 $ / shares	Jul. 12, 2018 $ / shares	Jun. 08, 2018 $ / shares	Mar. 08, 2018 USD ($)	Apr. 18, 2017 $ / shares	Jul. 01, 2013 USD ($)
Commitments And Contingencies [Line Items]
Purchase commitment amount under Insulin Supply Agreement | €									€ 90.3
Long Term Purchase Commitment Remaining Amount | €												€ 85.8
Supply Agreement expiration period								Dec. 31, 2024	Dec. 31, 2024
Supply Agreement renewal period								2 years	2 years
Purchase requirement amount for remaining current year | €												€ 4.4
Realized currency loss								$ 4,468,000		$ (13,641,000)	$ 3,433,000
Amount of net proceeds from issuance of securities											893,000
Operating lease rent expenses								$ 500,000		$ 400,000	$ 400,000
Lease Agreement with Enterprise | Vehicle Leases
Commitments And Contingencies [Line Items]
Number of vehicle leases | Vehicle							100
Operating lease rent expenses							$ 83,000
Lease expiration period							48 months
Common Stock
Commitments And Contingencies [Line Items]
Number of shares sold in underwritten public offering | shares				973,236
Purchase Agreements
Commitments And Contingencies [Line Items]
Stock purchase agreements date		Apr. 05, 2018
Purchase Agreements | Common Stock
Commitments And Contingencies [Line Items]
Number of shares sold in underwritten public offering | shares		14,000,000
Amount of net proceeds from issuance of securities		$ 26,400,000
Exchange price per share | $ / shares		$ 2.00
Purchase Agreements | Warrants
Commitments And Contingencies [Line Items]
Warrants to purchase of common stock | shares		14,000,000
Exercise price of warrants | $ / shares		$ 2.38
Foreign Currency Hedging Transaction
Commitments And Contingencies [Line Items]
Foreign currency hedging transaction renewable period								90 days	90 days
Cost of Goods Sold
Commitments And Contingencies [Line Items]
Amendment fee						$ 2,000,000
Other Income and Expense | Foreign Currency Hedging Transaction
Commitments And Contingencies [Line Items]
Realized currency loss								$ 600,000
Standby Letter of Credit | Vehicle Leases
Commitments And Contingencies [Line Items]
Maximum borrowing capacity																	$ 500,000
Collateralized amount under letter of credit																	$ 500,000
Amount drawn down on letter of credit						0		0
Deerfield
Commitments And Contingencies [Line Items]
Exchange price per share | $ / shares													$ 1.78	$ 2.04	$ 1.80	$ 1.96		$ 1.15
Deerfield | Milestone Rights Liability | Maximum
Commitments And Contingencies [Line Items]
Contingent liability for milestone payments						$ 90,000,000		$ 90,000,000											$ 90,000,000
Leerink Partners LLC | Underwriting Agreement
Commitments And Contingencies [Line Items]
Stock purchase agreements date	Dec. 19, 2018
Warrant expiration date	Dec. 26, 2019
Leerink Partners LLC | Underwriting Agreement | Common Stock
Commitments And Contingencies [Line Items]
Number of shares sold in underwritten public offering | shares	26,666,667
Amount of net proceeds from issuance of securities	$ 37,300,000
Exchange price per share | $ / shares	$ 1.50
Leerink Partners LLC | Underwriting Agreement | Warrants
Commitments And Contingencies [Line Items]
Warrants to purchase of common stock | shares	26,666,667
Exercise price of warrants | $ / shares	$ 1.60
Russell Ranch Road II LLC
Commitments And Contingencies [Line Items]
Operating lease rent expenses			$ 35,969		$ 40,951
Percentage of annual increase in lease payment			3.00%		3.00%
Lease expiration date			Jan. 31, 2023		Jan. 31, 2023
Lease renewal option			5 years		5 years
Maximum reimbursable amount for tenant improvements			$ 56,325